Tag Archives: communicating statistics

Applying medical research to clincial realities

Isabel recently asked over on Uterine rupture rates after 40 weeks:

“I wonder however if there are studies that compare the method of induction. My Doula said that the increase rates of uterine/ scar rupture was due to using high dosages of Pitocin, but now the induction uses lower dosages and administered at longer intervals. Do you know something about this?
Thank you”

 

Isabel,

Great question.

A few factors to consider:

1. Induction protocols can vary by provider, including some providers who don’t induced planned VBACs at all.
2. Induction guidelines can vary by hospital.
3. Women can react to the same drug/dose differently.
4. Some studies do compare the uterine rupture rates among spontaneous, induced, and augmented planned VBACs.

Medical studies on induction are only relevant to your situation if your provider follows the same protocol outlined in the study. However induction protocols are often not spelled out in detail unless that is the focus of the study.

When reading medical research, make special note of the sample size. We need ample participants in order to accurately capture and report the incidence of uncommon events such as uterine rupture. I typically like to see at least 3,000.  

Also remember that it’s ideal to have a experimental group (who receives the induction protocol) and a control group (who does not receive the induction protocol) in order to measure the difference in outcomes, such as fetal distress, uterine rupture, hemorrhage, cesarean hysterectomy, etc. Ideally, we would have a couple thousand, at least, in the experimental and control group.

In terms of the trend that induction now uses lower dosages and is administered at longer intervals, that may be true in some practices, but I would always confirm and not assume.

Anecdotally, I have heard a wide range of induction protocols reported just as research has identified similar variations among cesarean and episiotomy rates that are not linked to medical indication. This California Healthcare Foundation infographic clearly illustrates how hospitals differ:

Tale of Two Births

CLICK to share on Facebook

In terms of specific studies comparing the method of induction, the first resource that comes to mind is the Guise 2010 Evidence Report.

Search for the word Cytotec and there is a discussion comparing rates of rupture by Pitocin, prostaglandins, and Cytotec.

Pitocin is associated with the lowest rate of rupture among the chemical agents which is likely why ACOG (2010) recommends Pitocin and/or Foley catheter induction in planned VBACs when a medical indication presents. (Learn more about what the Pitocin insert actually says.)

There may be more recent studies out there. Google Scholar is a good place to start. You can often obtain the full texts of medical studies at your local library, university, or graduate school.

Also, if you subscribe to Evidence Based Birth’s newsletter, she will email you a crash course on how to find good evidence.

I hope this helps!

Jen

What is the induction protocol at your facility? Does it differ for those with a prior cesarean? Let me know in the comment section.

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American College of Obstetricians and Gynecologists. (2010). Practice Bulletin No. 115: Vaginal Birth After Previous Cesarean Delivery. Obstetrics and Gynecology, 116 (2), 450-463, http://dhmh.maryland.gov/midwives/Documents/ACOG%20VBAC.pdf

California Healthcare Foundation. (2014, Nov). A Tale of Two Births: High- and Low-Performing Hospitals on Maternity Measures in California. Retrieved from California Healthcare Foundation: http://www.chcf.org/publications/2014/11/tale-two-births

Guise, J.-M., Eden, K., Emeis, C., Denman, M., Marshall, N., Fu, R., . . . McDonagh, M. (2010). Vaginal Birth After Cesarean: New Insights. Rockville (MD): Agency for Healthcare Research and Quality (US). Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK44571/

Friedman, A. M., Ananth, C. V., Prendergast, E., Alton, M. E., & Wright, J. D. (2015). Variation in and factors associated with use of episiotomy. JAMA, 313(2), 197-199. Retrieved from http://jama.jamanetwork.com/article.aspx?articleid=2089343

Kozhimannil, K. B., Arcaya, M. C., & Subramanian, S. V. (2014). Maternal Clinical Diagnoses and Hospital Variation in the Risk of Cesarean Delivery: Analyses of a National US Hospital Discharge Database. PLoS Med, 11(10). Retrieved from http://journals.plos.org/plosmedicine/article?id=10.1371%2Fjournal.pmed.1001745

Induction is wrong, wrong, wrong… wait, what?

I hear all the time how induction in VBAC is contraindicated. This is false. This is the kind of misinformation that materializes when we demonize all induction rather than specifying that elective inductions are not worth the increased risks.

It’s important to use clear, specific language when we talk about birth because there is a lot of confusion among moms, advocates, doulas, and health care providers about VBAC and induction. When I point out the lack of clarity many people have on the topic to “anti-induction advocates” (for the lack of a better term), they respond with the fact that their focus is warning moms about elective inductions, which is absolutely needed. And they genuinely believe that people are aware of the distinction between elective and medically-indicated inductions. However, that has not been my experience, in fact it’s been quite the opposite.  There are many people who don’t understand the why, when, and how of inducing VBACs and that is impacting the abilities of women to make informed decisions and exercise their right of patient autonomy.

First, you can induce VBACs

To be clear, medically indicated induction in a VBAC is not contraindicated! Yet, many, many, many people persist that it is citing ACOG (1) and the Pitocin insert (2). ACOG clearly says in their latest VBAC guidelines (3) that “induction remains an option” in a mom planning a VBAC via Pitocin or Foley catheter. The Pitocin drug insert (2) does state, “Except in unusual circumstances, oxytocin [Pitocin] should not be administered in the following conditions” and then lists “previous major surgery on the cervix or uterus including cesarean section.” However, despite conventional wisdom, a prior cesarean is not listed under the contraindications section.  Further, the drug insert recognizes the value of individualized care:

The decision [to use Pitocin in a woman with a prior cesarean] can be made only by carefully weighing the potential benefits which oxytocin can provide in a given case against rare but definite potential for the drug to produce hypertonicity or tetanic spasm.

This is in line with ACOG’s latest VBAC recommendations (3) where they say, “Respect for patient autonomy supports the concept that patients should be allowed to accept increased levels of risk…” So this is information a woman can use to make an informed decision if she is faced with a medical condition that requires sooner rather than later delivery of her baby, but not necessarily in the next 15 minutes.  To induce, have a cesarean, or wait for spontaneous labor when facing a true medical issue is a decision for the mom to make in conjunction with her supportive heath care provider based on the evidence of her risks, benefits, and options.

My point is, if you just read bits and pieces of the insert, or a few key quotes from an anti-induction article, you are going to miss the full story; much like how reading the full text of a study gives you context and details that you lack by just reading the abstract.  Read my article (4) for more information on inducing VBACs.

Yet, misinformation persists

Ok, so now you know that induction remains an option per the Pitocin insert, ACOG, and respect for patient autonomy.  Now check out these quotes, from the last couple days, from six different people. If I were to keep a list of comments like these, just referring to induction and VBAC for a month, I would literally have dozens if not hundreds.  Misinformation is rampant:

“pitocin is CONTRAINDICATED for vbac bc the risk of uterine rupture”

“I thought it was unsafe to use pitocin with a vbac.”

“vbac should never be induced!”

“It is unsafe for prev surgical births. It says so in the PDR, or at least it did.”

“Not supposed to induce with a VBAC.”

“Never never never have an induction, especially with any kind of vbac!! Oh my goodness. it drastically raises your chances of uterine rupture!! Holy toledo. If you don’t know the risks involved with inductions, especially in vbacs, don’t offer the advice! Smh. Pitocin is completely contraindicated for vbacs, I’m pretty sure it even says that on the insert.”

“Are you actually trying to argue that induction of labour on a VBAC is OK???WOW…that is not evidence based AT ALL. Every study that has been done comparing the two shows a clear rise in risk associated with induction of labour and rupture. I am ALL for choice no matter the case, but I think every women has a right to INFORMED choice and you clearly are not. UNLIKE.”

Note the tone of these comments.  There is no room for negotiation.  Do you get the sense that they are just referring to elective inductions or all inductions? The message I get from these comments is loud and clear: these individuals believe that VBACs should not be induced. Period.

“Well, I would choose an induction…”

What is especially ironic is that some women who speak this way in public, privately share with me, that they themselves would opt for an induction over a repeat cesarean. Though do you see room for that option in any of the comments above?  They preserve that choice for themselves and yet pound the party line that all induction is always wrong and publicly deny that option to other women… for what purpose?  To maintain ad nauseam that induction is an evil, evil thing? Yes, apparently that is the case.

The last person’s comment was in response to me sharing my article (4) and saying that induction with medical indication does and should remain an option for moms planing VBACs.  Her reply equates my actions of sharing this reality with advocating against informed choice. How is keeping women in the dark about their options supporting the notion of informed consent? That faulty logic deserves a capitalized “WOW” with excessive exclamation points.

This is not the first person to say something like this to me. People so staunchly (and incorrectly) maintain that VBACs should never be induced because they have been indoctrinated to believe that induction is always wrong, it always introduces more risks.

More risk than what?

But the key question is: More risk than what? That is always what women should ask.

More risk than having a fetal demise before labor, partial placental abruption, or serious uterine infection and remaining pregnant? OK, so let’s say that is the truth.

Then any time any scarred woman has any of those medical conditions as well as those listed in my article (4), and they agree that remaining pregnant has higher risks that delivering the baby, they should have a cesarean, right? Even if vaginal birth remains an option, albeit via an induced labor?  Even if baby needs to be born sooner rather than later, but not necessarily in the next 15 minutes?  Those moms shouldn’t have a choice, they shouldn’t have a say, they should just go straight to cesarean?  How is that preserving choice for women?

Don’t misrepresent the facts

That is what these (extreme) “induction is wrong” proponents don’t understand. Induction has its place, as does every other medical intervention, and if you want to go straight to cesarean, rather than having a medically-indicated induction, fine.

But don’t misrepresent the truth to other women.

Don’t misrepresent what ACOG (1) or the Pitocin insert (2) says.

Don’t misrepresent the risks of Pitocin by listing a mish-mash of complications with no rates.  (How are women to understand the risks if you don’t tell them how frequently those emergencies occur?)

Don’t say things that can be disproved with a single mouse click like inducing VBACs is against evidence based medicine.

Don’t undermine a woman’s legal right to autonomy (5) by perpetuating the myth, that all induction, including when medically indicated, is wrong, wrong, wrong.

Don’t dictate specific actions while withholding facts that would enable women to make their own decisions, even if they are different that what you would prefer.

Medically indicated induction = choice

People don’t appreciate that standing for medically indicated induction is standing for women to have a choice: induction vs. repeat cesarean. Without induction, there is no choice when a valid medical reason presents. By eliminating the option of induction, women are mandated to the increasing risks (6) of repeat cesarean. And yet people who persist in their agenda say things like this to me (naturally, the following was asserted after I shared my article (4) and they didn’t read it),

Does inducing a VBAC increase the chance of rupture??? YES. Does a women, and should a women have the right to choose that irregardless of that FACT??? YES. Is the most important thing informed consent?? I believe it is.

Clear language provides clarity

So if people think that, then they should use clear, unambiguous language like, “Induction remains an option when a medical indication presents” or “Elective induction isn’t worth the increased risks” rather than flat out declaring “pitocin is contraindicated” (false) and claiming that induction in a VBAC is not evidenced based (false) as this very commenter did earlier in the thread. If someone maintains that it should be a woman’s choice, then they should share substantiated facts, context, statistics, and references, not erroneous blanket statements.

Women can make informed decisions only when they are informed

To provide information supports choice and informed consent. To dictate a specific action while misrepresenting the evidence eliminates choice and prohibits informed consent . I do not dictate to other women what they should do (7).

If you read my article (4), you will see that I list the reasons for medically indicated induction as well as provide an extensive review of studies illustrating the increased risk of uterine rupture. I do this rather than simply saying, “the risk of rupture is higher and thus you shouldn’t do it” because providing facts with context puts the choice in the hands of the mom, rather than me (or anyone else) dictating to her what she should do.

Some women will accept that higher rate of rupture in order to have a vaginal birth. Others will choose to accept the risks of a repeat cesarean section. Those are choices for women to make for themselves based on facts, not on misrepresentations of what other women (incorrectly) think is contraindicated.

“Induction is wrong” & patient autonomy

People who advocate that “induction is always wrong” don’t understand the implications of their assertions. By arguing against inductions, which in the minds of many include medically indicated inductions since no distinction is made, they are effectively advocating for more cesareans and against informed consent and patient autonomy. The mission of VBAC Facts is to make hard-to-find, interesting, and pertinent information relative to post-cesarean birth options easily accessible to the people who seek it. I advocate for informed consent and patient autonomy and that is why I share evidence (4) rather than dictating what others should do. I only hope that this reasoning and evidence based position spreads because there are far to many people out there who persist in the inaccurate philosophy that inductions in a VBAC are always wrong even in the face of a valid medical reason. This does not support choice, women, or birth.

I profusely apologize for the excessive underlining in this article, but I think you will agree, that it was absolutely necessary.

Sources

1. Kamel, J. (2010, Jul 21). ACOG issues less restrictive VBAC guidelines. Retrieved from VBAC Facts: http://vbacfacts.com/2010/07/21/acog-issues-less-restrictive-vbac-guidelines/

2. JHP Pharmaceuticals LLC. (2012, Sept). Pitocin official FDA information, side effects and uses. Retrieved from Drugs.com: http://www.drugs.com/pro/pitocin.html

3. American College of Obstetricians and Gynecologists. (2010). Practice Bulletin No. 115: Vaginal Birth After Previous Cesarean Delivery. Obstetrics and Gynecology , 116 (2), 450-463. Retrieved from Our Bodies Our Blog: http://www.ourbodiesourblog.org/wp-content/uploads/2010/07/ACOG_guidelines_vbac_2010.pdf

4. Kamel, J. (2012, May 27). Myth: VBACs should never be induced. Retrieved from VBAC Facts: http://vbacfacts.com/2012/05/27/myth-vbacs-should-never-be-induced/

5. Kamel, J. (n.d.). Legal stuff. Retrieved from VBAC Facts: http://vbacfacts.com/category/vbac/legal-stuff

6. Kamel, J. (2012, Dec 9). Why cesareans are a big deal to you, your wife, and your daughter. Retrieved from VBAC Facts: http://vbacfacts.com/2012/12/09/why-cesareans-are-a-big-deal-to-you-your-wife-and-your-daughter/

7. Kamel, J. (2012, Dec 7). Some people think I’m anti-this/ pro-that: My advocacy style. Retrieved from VBAC Facts: http://vbacfacts.com/2012/12/07/some-people-think-im-anti-thispro-that-my-advocacy-style/

 

Evening primrose oil: “Don’t use it if you are pregnant?”

Note: After I published this article, it came to my attention that there was one other study on the oral use of EPO in pregnant woman.  You can read more about this second study in the comments section below.

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Many moms and midwives use evening primrose oil (EPO) for cervical ripening. So I was absolutely shocked at the complete lack of evidence on the effectiveness and safety of EPO use among pregnant women. There is one study that examined the oral use EPO and it’s ability to ripen the cervix during pregnancy. It concluded EPO didn’t work as we expected it to and further, women who took EPO were more likely to experience a whole host of complications. Shockingly, there are no studies on the vaginal use of EPO and it’s effect on ripening the cervix during pregnancy. In short, there is insufficient clinical evidence documenting the risks and benefits of EPO and without that information, should pregnant women take it?

The two studies that have examined cervical ripening via oral EPO

Paula Senner gives an excellent review of this single study in her Quantitative Research Proposal entitled, “Oral Evening Primrose Oil as a Cervical Ripening Agent in Low Risk Nulliparous Women” (emphasis mine),

A study by Dove and Johnson (1999) investigated the use of evening primrose oil on the length of pregnancy and selected intrapartum outcomes at an American free-standing birth center in low-risk nulliparous women. More specifically, the study examined the effect of oral evening primrose oil on length of pregnancy, length of labor, incidence of postdates induction, incidence of prolonged rupture of membranes, occurrence of abnormal labor patterns, and cesarean delivery.

A two group retrospective quasiexperimental design was conducted on a sample drawn from the records of all nulliparous women at a free-standing birthing center over a seven year period from 1991 to 1998. All of the records were screened for accurate gestational age dating, cephalic presentation, low risk status and delivery between 38 and 42 weeks gestation. The study group consisted of 54 women who took oral evening primrose oil in their pregnancy (500 mg three times a day starting at 37 weeks gestation for the first week of treatment, followed by 500 mg once a day until labor ensued), and the control group was composed of 54 women who did not take anything. Antepartum and intrapartum records of all women were reviewed focusing on the above identified criteria.

Differences between measured variables of maternal age, Apgar score, birth weight, length of pregnancy, and length of labor were tested… Results showed no significant differences between the evening primrose oil group and the control group on age, Apgar score, or days of gestation (P>.05)… This retrospective chart review showed no benefit from taking oral evening primrose oil for the purpose of reducing adverse labor outcomes or for reduction of length of labor.

The study’s abstract gives us more details on the its findings (emphasis mine):

Findings suggest that the oral administration of evening primrose oil from the 37th gestational week until birth does not shorten gestation or decrease the overall length of labor. Further, the use of orally administered evening primrose oil may be associated with an increase in the incidence of prolonged rupture of membranes, oxytocin [Pitocin] augmentation, arrest of descent, and vacuum extraction.

The second study found that while women who took EPO experienced a greater degree of cervical ripening, that did not result in a shorter pregnancy or labor: “There was no significant difference in the interval from onset or end of treatment to onset of labor between the two groups” (Ty-Torredes, 2006).

So one study on oral EPO found that it doesn’t work as we thought it did and it offers considerable risks.  The other study found that it does result in some cervical ripening, but that did not translate into shorter pregnancies or labors.

As a result, a December 2009 article published in the American Family Physician recommended,

The use of evening primrose oil during pregnancy is not supported in the literature and should be avoided.

Medline Plus, a website published by the US National Library of Medicine and the National Institutes of Health, published an April 2012 article on EPO.  Medline echoes the sentiments of the American Family Physician article when it said there was,

insufficient evidence to rate effectiveness for [EPO during pregnancy and] research to date suggests that taking evening primrose oil doesn’t seem to shorten labor, prevent high blood pressure (pre-eclampsia), or prevent late deliveries in pregnant women… [Further,] taking evening primrose oil is POSSIBLY UNSAFE [their emphasis] during pregnancy.  It might increase the chance of having complications. Don’t use it if you are pregnant [emphasis mine.]

Bleeding issues could complicate cesareans

Research on the use of EPO for other aliments among non-pregnant people has suggested there could be a possible association between the use of EPO and bleeding problems during surgery. As a result, Medline recommends that people don’t use it at least 2 weeks before a scheduled surgery.

This poses a special problem for women using EPO during the last weeks of pregnancy. Since we cannot predict who will have a vaginal birth and who will have a cesarean, it is important to consider that EPO could contribute to hemorrhage during a cesarean and possibly even during a normal vaginal delivery. We just don’t know because there is a lack of data.

Dosages and mode of delivery

Another hole in the research and our knowledge relates to dosage.  I see women reporting an incredible range of dosages on the internet.  What is safe?  There are no clinical studies documenting how much women should take.  Maybe X dose of EPO is good, but Y dose introduces XYZ risks.  How long should women take EPO?  The last month of pregnancy?  The last two weeks?  (Remember, we just read how there is a possible bleeding issue.)  Should they take it twice a day or once a day?  Does the body absorb or metabolize EPO differently if it is administrated vaginally or orally?  Does it make a difference if the woman using EPO has a scar on her uterus?  Or multiple scars?  We just don’t know the answers to these questions.

What about our bodies’ innate ability to birth?

It comes down to the fundamental question: Do our bodies need something to help us go into labor? Many natural birth advocates reject the routine use of Pitocin augmentation during labor because they say our bodies know how to birth.  Yet it’s often women from this same mindset that use EPO. Either our bodies work as is, or they don’t.  Either we need something to help us go into labor – whether that is EPO or Pitocin – or we don’t.

Are we less leery of EPO because it comes from a flower?  Because midwives suggest it more than OBs?  Because we can purchase it over the counter?  Because it’s a pill, not an injection?  Because we can administer it to ourselves in the comfort of our home?  Because it’s not produced by “big pharma?”  Because it is used so routinely that no one questions it?  Or is it simply because we all assume since everyone takes it, the evidence must be on the side of EPO?

On (the lack of) evidence: Holding ourselves to the same standard

When I have shared the lack of evidence on EPO’s ability to ripen cervixes or prepare a woman’s body for labor, sometimes women reply with “But there is none [evidence] to suggest it won’t [help] either…….” American OBs used this same rationale when they induced scarred moms with Cytotec in the 1990s. There were no published medical studies on Cytotec induction in scarred women, so we didn’t know the risks and benefits. But people used it because we knew it caused uterine contractions. What can go wrong, right?

But the problem is, when there is a lack of clinical evidence on large populations of women, we are sometimes surprised with dire outcomes that no one could have predicted as was the case of Cytotec.  We cannot look back at that period and think, “How could they have done that” when we are now doing the same thing with EPO: using a chemical without evidence of its benefits and harms.

Some rail against “the medical system” because Pitocin/ultrasound/etc hasn’t been “proven safe,” yet we use EPO with no evidence that it does what we think it does, no evidence that it is safe, and the limited evidence we do have says that it’s associated with a variety of complications.

As Hilary Gerber D.O. aka Mom’s Tin Foil Hat says,

As someone who spent many years in the natural supplements industry, I agree that we need to hold natural products to the same scrutiny.

Also, most EPO is extracted with solvents like hexane. I am much more supportive of natural products or interventions that have been used in that form or method for generations (e.g. sexual intercourse at term, ingesting a substance that is a common food item, etc) than a chemically extracted, concentrated, unstudied substance.

Anecdote vs. evidence

OBs who used Cytotec on scarred women in the 1990s inevitably would have said, “I haven’t had a bad outcome yet,” and I suspect that many people who use EPO now would say the same thing.  When we have one woman who used EPO and had an arrest of descent, do care providers recognize that this could be as a result of the EPO?  When we have one women who used EPO and it worked as expected, how can we determine her labor progressed because of the EPO?

When you have a small sample size, it’s hard to make a connection.  It’s even more difficult to connect EPO to it’s possible list of complications when not many care providers are aware of the lack of evidence on EPO and the findings of this one lone study.  Is our limited experience, with relatively few patients, without meticulous record keeping that can detect patterns across groups of patients, sufficient evidence?  I don’t think so.  We would likely need thousands of women in order to create a sample size powerful enough to detect – or rule out – common and more rare EPO complications in addition to answering the many questions I posed above.

Take away message

I’m not saying to use EPO or not.  I’m simply pointing out how little we know about this commonly used substance and questioning if that should make a difference in how we view and/or use it.

There is limited evidence on EPO’s ability to ripen the cervix and aid with labor.  We have two studies on the oral use of EPO that looked at this question and none on the vaginal use of EPO among pregnant women.  This is reason enough to not use it.

We have no evidence on an appropriate or safe dosage (if that exists).

We have no evidence on the risks and benefits of oral vs vaginal administration.

In order to make the association between EPO and complications, care providers need to be aware of the complications with which EPO may be associated.

Let’s review the research that does exist.  One study found that EPO doesn’t ripen the cervix and poses considerable risk.  Another study found that EPO does ripen the cervix but those women did not go into labor sooner than the women that didn’t take EPO. We need more large studies to confirm or refute the notion that EPO = ripen cervix = shorter pregnancies. Without that information, we are using a product that we know very little about.

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Bayles, B., & Usatine, R. (2009, Dec 15). Evening Primrose Oil. American Family Physician, 80(12), 1405-1408. Retrieved from http://www.aafp.org/afp/2009/1215/p1405.html

Dove, D., & Johnson, P. (1999, May-Jun). Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women. Journal of Nurse-Midwifery, 44(3), 320-4. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10380450

Gerber, H. (2012, November 13). Facebook comments on evening primrose oil.

McFarlin, B. L., Gibson, M. H., O’Rear, J., & Harman, P. (1999, May-Jun). A national survey of herbal preparation use by nurse-midwives for labor stimulation. Review of the literature and recommendations for practice. Journal of Nurse Midwifery, 44(3), 205-16. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10380441

Medline Plus. (2012, Apr 10). Evening primrose oil. Retrieved from Medline Plus: A service of the U.S. National Library of Medicine & National Institutes of Health: http://www.nlm.nih.gov/medlineplus/druginfo/natural/1006.html

Senner, Paula. (2003, December). Oral Evening Primrose Oil as a Cervical Ripening Agent in Low Risk Nulliparous Women. Retrieved from Frontier School of Midwifery and Family Nursing, Philadelphia University: http://www.instituteofmidwifery.org/MSFinalProj.nsf/a9ee58d7a82396768525684f0056be8d/f44c26c0836acbb585256dd1006b2a22?OpenDocument

Ty-Torredes, K. A. (2006). The effect of oral evening primrose oil on bishop score and cervical length among term gravidas. AJOG, 195(6), S30. Retrieved from http://www.ajog.org/article/S0002-9378%2806%2901323-8/fulltext

Wagner, Marsden. (1999). Misoprostol (Cytotec) for Labor Induction: A Cautionary Tale. Retrieved from Midwifery Today: http://www.midwiferytoday.com/articles/cytotecwagner.asp

Does the term “TOLAC” tweak you?

On the acronym TOLAC (trial of labor after cesarean)….

Some studies break out statistics in four ways.

1. ERCS/D (elective repeat cesarean section/ delivery)
2. VBAC (vaginal birth after cesarean)
3. CBAC (cesarean birth after cesarean aka cesarean after planned VBAC)
4. TOLAC (VBAC + CBAC stats)

Because we are unable to predict who will have a VBAC or CBAC, the TOLAC stat enables us to review outcomes from a variety of angles:

  • TOLAC vs. ERCS
  • VBAC vs. ERCS
  • CBAC vs. ERCS

Some women find the TOLAC acronym offensive, because it implies “trying,” so practitioners sensitive to this may way to use the phrase “planning a VBAC.”   Understanding that TOLAC isn’t a dig at moms, but just a straightforward, objective term that care providers use, can (hopefully) take the sting out of the word.

Remember, your care provider is not your girlfriend.  They use clinical terms because that is the language of their world. They speak like clinicians because they are clinicians. All that said, providers who are aware of how the term TOLAC is received by some women use the term “planned VBAC.”

So moms, you use the language that works for you! Just remember that TOLAC is really more of a clinical term and when your provider uses it, it doesn’t necessarily mean that they are a jerk.  They just may have forgotten to code switch from clinical to sensitive language.

Moms don’t typically say, “I’m so excited for my TOLAC!” However, if you do, you might make your provider laugh and connect with them on a human level.

Two points for the person who knows how this picture is relevant…

20120808-102648.jpg

False comparison: Fatal car accidents and VBAC

RETRACTION/ CORRECTION: I originally posted this article challenging the thought that you are more likely to die in a fatal car accident than during a VBAC.  I tried to crunch the numbers in the way that I felt most accurate.  However, it has been bugging me ever since because there is no accurate way to compare these two events and I should have emphasized that more. We can accurately and fairly compare the risks of VBAC to the risks of a repeat cesarean or the risks of a first time time mom.  However, it is a misleading to compare the risks of birth to non-birth events because they are to different.  While I did discuss this at great length at the end of this article, the title I originally chose (Myth: Mom more likely to die in car accident than VBAC) just continued to feed this false comparison.  I have since updated the article and title.  I apologize for any confusion I caused.

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On fatal car accident statistics: There are many, many variables that factor into an individual’s risk of dying in a car accident.  The most accurate way to calculate your risk is by miles driven.  To learn more, please refer to the National Motorists Association’s document “Understanding Highway Crash Data.” I use the figures below in order to get an average rate for the purpose of discussion.

On terminology: Read why I use the term TOLAC.

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Prepare yourself for yet another installation to the Birth Myth series.  I’ve heard this sentiment many times over the years and I’m sure you have too.   The well-meaning people who share this “statistic” simply desire to give moms seeking information on VBAC some encouragement:

If your husband is worried about you dying during a VBAC, tell him you are four times more likely to die in a car accident on your way home from work today.  Sorry if that sounds morbid, but the odds of the mother dying in a VBAC are truly minuscule.

Another article (filled with inaccurate statements, contradictions, and oodles of statistics without sources) recently making the rounds on Facebook says one of the risks of hospital birth is the 1:10,000 risk of a fatal car accident on the way to the hospital.

While these statements are very comforting, as birth myths tend to be, they are false comparisons.  We can accurately and fairly compare the risks of a TOLAC to the risks of a repeat cesarean or the risks of a first time time.  However, it is a misleading to compare the risks of birth to non-birth events.

Comparing unlike risks

Many birth advocates try to weigh the event of uterine rupture against other life events in an attempt to give context, but this is a misleading and inaccurate comparison.  Andrew Pleasant in his article entitled, Communicating statistics and risk, explains:

Try not to compare unlike risks.  For instance, the all-too-often-used comparison ‘you’re more likely to be hit by a bus / have a road accident than to…’ will generally fail to inform people about the risks they are facing because the situations being compared are so different.  When people assess risks and make decisions, they usually consider how much control they have over the risk.  Driving is a voluntary risk that people feel (correctly or not) that they can control.  This is distinctly different from an invisible contamination of a food product or being bitten by a malaria-carrying mosquito.

Comparing the risk of a non-communicable disease, for example diabetes or heart disease, to a communicable disease like HIV/AIDS or leprosy, is similarly inappropriate.  The mechanisms of the diseases are different, and the varying social and cultural views of each makes the comparison a risky communication strategy.

Take away message: Compare different risks sparingly and with great caution because you cannot control how your audiences will interpret your use of metaphor.

Comparing lifetime/annual risk to your risk of something happening over a day (or two)

Your annual or lifetime risk of something happening will often be higher than your risk of a birth related complication.  But this is because the annual risk of something measures your risk for 365 days.  The lifetime risk of something is often based on 80 years.  You are likely to be in active labor for one day, maybe two.  To compare the risk of something that happens over 1-2 days to the aggregate risk of something that could happen any day over 365 days or 80 years is unfair and confusing.

Look at something like your lifetime risk of breast cancer which is often quoted as 1 in 8.  So one could easily say, “Hey, I have a greater risk of breast cancer over my lifetime than I do have a uterine rupture!”  But, let’s look at this a bit more:

Again, I refer to Andrew Pleasant’s article, Communicating statistics and risk:

An oft-reported estimate is the lifetime breast cancer rate among women. This rate varies around the world from roughly three per cent to over 14 per cent.

In the United States, 12.7 per cent of women will develop breast cancer at some point in their lives. This statistic is often reported as, “one in eight women will get breast cancer”. But many readers will not understand their actual risk from this. For example, over 80 per cent of American women mistakenly believe that one in eight women will be diagnosed with breast cancer each year.

Using the statistic ‘one in eight’ makes a strong headline but can dramatically misrepresent individual breast cancer risk.

Throughout her life, a woman’s actual risk of breast cancer varies for many reasons, and is rarely ever actually one in eight. For instance, in the United States 0.43 per cent of women aged 30–39 (1 in 233) are diagnosed with breast cancer. In women aged 60–69, the rate is 3.65 per cent (1 in 27).

Journalists may report only the aggregate lifetime risk of one in eight because they are short of space. But such reporting incorrectly assumes that readers are uninterested in, or can’t comprehend, the underlying statistics. It is critically important to find a way, through words or graphics, to report as complete a picture as possible.

Take away message: Be extra careful to ensure your readers understand that a general population estimate of risk, exposure or probability may not accurately describe individual situations. Also, provide the important information that explains variation in individual risk. This might include age, diet, literacy level, location, education level, income, race and ethnicity, and a host of other genetic and lifestyle factors.

To compare events that are so different like the risk of a fatal car accident and the risk of TOL maternal mortality is inaccurate and doesn’t help moms understand their options.  Your risk of a car accident depends on how much you drive, when you drive, if you are distracted or on medication, etc, etc, etc.  The variables that impact your risk of dying during a  TOLAC are very different.  However, one way these two events are similar:  Sometimes we can make all the “right” or “wrong” decisions and the element of luck will sway us towards a good or bad outcome.

The problems with birth myths and false comparisons

False comparisons and birth myths like this are shared with the best of intentions.  So often the risks of VBAC are exaggerated for reasons having nothing to do with the health of baby and mom.  Birth advocates share these myths (which they believe to be true) as a way of boosting the morale of moms seeking VBAC as these moms are constantly faced with a barrage of unsupportive comments from family, friends, and even care providers.

The problem is, women make plans to have (home) VBAC/VBAMC based on these myths.  They make these plans because birth myths make the risk of VBAC, uterine rupture, infant death, and maternal death look practically non-existent.  That is dangerous.

Perpetuating these myths impedes a mom’s ability to provide true informed consent.  If a mom thinks her risk of uterine rupture is similar to a unscarred mom or a unscarred, induced mom, or less than her risk of getting struck by lighting or bitten by a shark, she does not have accurate picture of the risk.  And if she doesn’t understand the risks and benefits of her options, she is unable to give informed consent or make an informed decision.

Birth advocates get all up in arms about the mom who plans an elective, primary cesarean section without “doing her research.”  Or the mom who consents to an induction at 38 weeks because her OB “said it was for the best.”  Or when an OB coerces a mom into a repeat cesarean by saying the risk of uterine rupture is 15%.  Shouldn’t we be just as frustrated when moms plan (home) VBACs based on misrepresentations of the truth?  Shouldn’t we hold ourselves to the same standard that we expect from others?

The second problem with perpetuating these false comparisons and myths is that once women learn the true risks, they seem gigantic in comparison to the minuscule risk they had once accepted.  Now VBAC seems excessively risky and some loose confidence in their birth plans.  Birth advocates do not support moms by knowingly perpetuating these myths.  The reality is, the risks of VBAC are low.  We don’t need to exaggerate or minimize the benefits or risks of VBAC.  If we just provided women with accurate information from the get go, they would be able to make a true, informed decision.

The third problem is that we really look dumb when we say stuff like this.  If we want to be taken seriously, we really need to double check what we pass on.  I encourage you to ask for a source when someone says something that sounds to good to be true or just plain fishy.  (And hold me to the same standard!)  I often ask people for a source for their assertions… with varying results.

Sometimes people have a credible source available and share it with me.  I learn more and it’s all good.  Other times, people get angry.  They think I’m challenging them or trying to argue with them.  But the truth is, I’m just trying to learn. What I have found is, when people get angry, it’s sometimes because they don’t have a source and they are insulted that I didn’t accept their statement at face value.  They have just accepted what a trusted person told them as the truth and expect me to do the same.

Doesn’t it strike you as odd that some people encourage the continual questioning OBs and the medical system, yet expect you to accept what they say as The Truth no questions asked?   “Question everyone but me.”  Why?  Why is it when we question an OB, that’s a good thing, yet when we hold our birthy friends and colleagues to the same standard, that is being argumentative?  I say, ask for the source.  From everyone.

Take away messages

It is inaccurate and misleading to compare two events that are as different as a fatal car accident and TOL maternal mortality.  Period.

Let’s stop this false comparison and bring us back to what we should be comparing TOLAC/VBAC to: the risks of a repeat cesarean.

When women plan a VBAC based on false information,  their confidence can be shattered when they learn that the risk of uterine rupture and maternal death are much higher than they were lead to believe.

When women plan a VBAC based on false information, they are deprived of their right to informed consent.

While the risk of scar rupture is very different than the risk of a fatal car accident, it is similar to other serious obstetrical emergencies such as placental abruption, cord prolapse, and postpartum hemorrhage.

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Guise J-M, Eden K, Emeis C, Denman MA, Marshall N, Fu R, Janik R, Nygren P, Walker M, McDonagh M. Vaginal Birth After Cesarean: New Insights. Evidence Report/Technology Assessment No.191. (Prepared by the Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-2007-10057-I). AHRQ Publication No. 10-E003. Rockville, MD: Agency for Healthcare Research and Quality. March 2010.   http://www.ahrq.gov/downloads/pub/evidence/pdf/vbacup/vbacup.pdf

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For those who are interested in the reasoning and mathematics from the original article:

But, if we were going to compare the unlike risks of a fatal car accident and TOLAC, this is how I would do it: compare the daily risks of the events.

Maternal death and TOL

Per the report presented at the 2010 NIH VBAC conference entitled Vaginal Birth After Cesarean: New Insights (Guise, 2010):

Overall rates of maternal harms were low for both TOL [trial of labor] and ERCD [elective repeat cesarean delivery]. While rare for both TOL and ERCD, maternal mortality was significantly increased for ERCD at 13.4 per 100,000 versus 3.8 per 100,000 for TOL . . . The rate of uterine rupture for all women with prior cesarean is 3 per 1,000 and the risk was significantly increased with TOL (4.7/1,000 versus 0.3/1,000 ERCD).

Put another way, there is a 0.0038% (1 in 26,316) risk of maternal death during a trial of labor.  For a mom to die is very rare.

Risk of a fatal car accident

Of the 311,000,000 people living in the US (US Census, 2012), about 40,000 die annually (Beck, 2006) from car accidents in the United States which gives us a annual rate of 0.0129% (1 in 7,752).  (But remember, this is a very rough representation of the risk due to all the factors I previously mentioned.)

Many women look at this number and say, “See, you are more likely to die in a car accident than during a TOL.”

But remember, 0.0129% (1 in 7,752) is the annual rate of Americans dying due to car accidents.

To compare something like your annual risk of a fatal car accident to your risk of dying during a TOL is an unfair and inaccurate comparison.   It would be more accurate (though still a false comparison) to compare your daily risk of a fatal car accident (because most people travel in a car every day) to the risk of maternal death during a TOL because you are not in labor every day for a year.  Let me explain.

Comparing TOL maternal mortality to fatal car accidents

Often this false comparison is expressed as, “You are more likely to have a fatal car accident on the way to the hospital than have a uterine rupture or die during a VBAC.”  But the risk of a fatal car accident on the day you drive to the hospital is not 1 in 7,752.  That is your risk over a year.  We have to estimate your risk on that day you drive to the hospital by dividing 0.0129% by 365 days which equals 0.00003534% or 1 in 2,829,458.

No matter what stat we use from any study, the risk of maternal mortality during a TOL is much greater.  (But remember, this is a false comparison anyways!)

Guise’s data pegs the risk at 0.0038% or 1 in 26,316 which is 107.5 times greater than the risk of a fatal car accident as you drive to the hospital in labor.  This does not mean that the risk of dying during a TOL is so large, but rather our daily risk of a fatal car accident is so small that it’s literally theoretical.  (Read Kim James’ “Understanding obstetrical risk” for more.)

What about the risk of uterine rupture?

Using the 0.47% (1 in 213 TOLs) risk of scar rupture (Guise, 2010), the risk of a fatal car accident is 13,283 times smaller.

Why don’t we spread the risk of rupture/maternal mortality across the entire pregnancy?

After I initially published this article, someone left this great comment on Facebook:

I get this, but I also get why using annual stats of car accidents would be accurate when you are looking at uterine rupture rates themselves and not just during TOL, since a risk of rupture exists throughout pregnancy and not just during labor and mom would be pregnant for approximately 10 months or more.

I wondered about the best way to crunch the numbers because these events are so different and thus so difficult to compare.  In the end, it is a false comparison, but here was my original thinking….

Most Americans are in a car everyday, so they have that risk – no matter how small – every day unless they are not in a car in which case their risk is zero.  The risk is primarily associated with being in a car.

The risk of uterine rupture and maternal mortality is primarily associated with being in labor, so we can’t spread the risk of rupture/maternal mortality across the whole pregnancy because the risk of rupture/maternal mortality is not the same from conception to delivery.

One study examined 97% of births that occurred in the The Netherlands from 1st August 2004 until 1st August 2006 and found that 9% (1 in 11) of scar ruptures happened before the onset of labor. When we take 9% of the overall rate of scar rupture 0.64% (1 in 156) (including non-induced/augmented, induced, and augmented labors), we get a 0.0576% (1 in 1736) risk of pre-labor scar rupture and a 0.5824% (1 in 172) risk of rupture during labor (Zwart 1009). Since the risk of rupture is not the same over the entire pregnancy and labor, we cannot accurately calculate a daily risk of rupture.

In other words, the risk of rupture is rare before labor (0.0576% or 1 in 1736) and then becomes uncommon when labor begins (0.5824% or 1 in 172).  Even though we could go into labor anytime during pregnancy, the risk before we go into labor is so small in comparison to the risk when we actually go into labor.

Can you feel a uterine rupture with an epidural?

woman-laboring-hospitalSome care providers discourage epidurals in VBAC moms fearing that it will mask the symptoms of uterine rupture (namely abdominal pain) and delay diagnosis resulting in a poor outcome for baby and to a lesser extent, mom  Other care providers suggest or even require VBAC moms to have an epidural so that a cesarean can quickly take place if needed.  Which philosophy does the evidence support?

Review of 14 VBAC studies

I recently came across a study entitled “The Role of Epidural Anesthesia in Trial of Labor” (Johnson, 1990) that reviewed 14 VBAC studies.  Johnson found among scarred women who ruptured, a greater percentage of women with epidurals reported abdominal pain than women without epidurals.

  • 5 of 14 (35.7%) patients with an epidural who ruptured had abdominal pain.
  • 4 of 23 (17.4%) patients without an epidural who ruptured had abdominal pain.

Interestingly, only 22% of the women who ruptured in that study reported abdominal pain and Johnson concluded, “Thus abdominal pain is an unreliable sign of complete uterine rupture.”  But is it?  69% of women in Zwart (2009) reported abdominal pain. (I write about Zwart here and here.)

One difference between the studies is Zwart included significantly more scarred moms than Johnson: 26,000 versus 10,976.  The second different is that Zwart also included 332,000 unscarred women representing 93% of the sample population.

Unscarred moms, uterine rupture, and abdominal pain

I’m curious if the reason why Zwart reported such a high level of abdominal pain was because it included so many unscarred moms.  I wonder if unscarred moms are more likely to report pain and if so, why would that be.  Zwart combines the symptoms for scarred and unscarred rupture into one chart.  If they broke that chart out by scarred vs. unscarred rupture symptoms, would we see any major differences? Generally, unscarred rupture does more damage to the uterus and is more likely to result in an infant death (Zwart, 2009), so maybe because there is more damage, women report more abdominal pain?

Most common UR symptom: fetal heart tone abnormalities

I checked out  eMedicine’s article “Uterine Rupture in Pregnancy” and was fascinated to learn that several studies concur with Johnson.  They also found that abdominal pain is reported at a much lower rate than fetal distress/ abnormal fetal heart tones:

…sudden or atypical maternal abdominal pain occurs more rarely than do decelerations or bradycardia. In 9 studies from 1980-2002, abdominal pain occurred in 13-60% of cases of uterine rupture. In a review of 10,967 patients undergoing a TOL, only 22% of complete uterine ruptures presented with abdominal pain and 76% presented with signs of fetal distress diagnosed by continuous electronic fetal monitoring. [This is the Jonhson study.]

Moreover, in a study by Bujold and Gauthier, abdominal pain was the first sign of rupture in only 5% of patients and occurred in women who developed uterine rupture without epidural analgesia but not in women who received an epidural block.  (Bujold E, Gauthier RJ. Neonatal morbidity associated with uterine rupture: what are the risk factors?. Am J Obstet Gynecol. Feb 2002;186(2):311-4).  Thus, abdominal pain is an unreliable and uncommon sign of uterine rupture. Initial concerns that epidural anesthesia might mask the pain caused by uterine rupture have not been verified and there have been no reports of epidural anesthesia delaying the diagnosis of uterine rupture.

A 2012 study out of the UK (Fitzpatrick, 2012) also reported that 76% of uterine ruptures were accompanied by fetal heart rate abnormalities in comparison to 49% reporting abdominal pain.

ACOG’s stance on epidurals

It’s important to note that ACOG does support the use of epidurals in VBACs:

Epidural analgesia for labor may be used as part of TOLAC, and adequate pain relief may encourage more women to choose TOLAC (109, 110). No high quality evidence suggests that epidural analgesia is a causal risk factor for an unsuccessful TOLAC (44, 110, 111). In addition, effective regional analgesia should not be expected to mask signs and symptoms of uterine rupture, particularly because the most common sign of rupture is fetal heart tracing abnormalities (24, 112).

Remember that fetal heart tracing abnormalities were detected in 76% of the ruptures in Johnson ad 67% of the ruptures in Zwart.

I couldn’t find any mention of epidurals masking rupture pain in the Guise 2010 Evidence Report, but found that the Johnson study was excluded from their report because “No full-text paper, opinion or letter with no data.”  Interesting.

Uterine rupture symptoms

A list of uterine rupture symptoms and their frequency per Medscape’s article on uterine rupture.

  • “80% Prolonged deceleration in fetal heart rate or bradycardia
  • 54% Abnormal pattern in fetal heart rate
  • 40% Uterine hyper-stimulation
  • 37% Vaginal bleeding
  • 26% Abdominal pain
  • 4% Loss of intrauterine pressure or cessation of contractions”

A couple notes.  One, abdominal pain is not a consistent or reliable symptom of UR.  Two, there is a level of interpretation that goes into diagnosing abnormal fetal heart tones even among people who have extensive medical training.

Additional symptoms that I have collected from other sources include:

  • Baby’s head moves back up birth canal
  • Bulge in the abdomen or under the pubic bone (where the baby may be coming through the tear in the uterus)
  • Uterus becomes soft
  • Shoulder pain

Risks and benefits of epidurals

As with every option available to you regarding birth, it’s always good to be knowledgeable on the risks and benefits of epidurals so you can make an informed choice.  Three excellent resources are this article by Sarah Buckley MD, the PubMed Health Epidural Fact Sheet and this review of epidural research by the Cochrane Library.

Take home message

The limited information available tells us that epidurals do not mask abdominal pain from uterine rupture.

The most common symptom of uterine rupture is fetal distress diagnosed by fetal heart rate abnormalities.

Epidurals may be used during a trial of labor after cesarean per ACOG.

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As always, if you can offer further research or perspective on this topic, please leave a comment.  Our knowledge is constantly growing and we can only work with the best information available to us now.  Who knows what future research will tell us?

Myth: Two numbers less than 1% are similar

I have often heard, “If two numbers are less than 1%, they are similar.”  Typically
this is expressed while comparing the risks of rupture in an unscarred versus scarred uterus.   But is this true?  How different can two numbers less than 1% be?calculator-983900_1920

Two numbers less than 1% are no more similar than two numbers greater than 1%

Just because two numbers are less than 1%, that doesn’t make them any more similar than two numbers greater than 1%.  A 2% risk of something happening is very different than an 89% risk.  While they are both greater than 1%, they represent drastically different levels of risk.

2% = 1 in 50 risk

89% = 1 in 1.12 risk

89% represents a 44 times greater risk than 2%.

What about numbers less than 1%?

It might seem rational that since numbers less than 1% are so small, that there wouldn’t be as much of a difference between them.  But numbers less than 1% work in the same way as those greater than 1%.   Let’s run a few and measure the difference.

1 in 100 represents 1%.

1 in 1,000, is the same as 0.1%, and is 10 times smaller than 1%.

1 in 10,000, is the same as 0.01%, and is 100 times smaller than 1%.

1 in 100,000, is the same as 0.001%, and is 1,000 times smaller than 1%.

1 in 1,000,000, is the same as 0.0001%, and is 10,000 times smaller than 1%.

Comparing small risks

According to Zwart* (2009), the risk of uterine rupture in:

– an unscarred mom is 1 in 14,286 (0.007% or 0.7 in 10,000) and

– a scarred mom is 1 in 156 (0.64% or 64 in 10,000).

(Both statistics include non-induced/augmented, induced, and augmented labors.)  Even though both numbers are less than zero, they represent very different levels of risk.  In fact, the risk of rupture in an unscarred mom is 91 times smaller than a scarred mom.  It’s not that the risk of rupture is excessively high in a scarred mom, but that it is so very, very, very low in an unscarred mom.

Using the language from Kim James’ handout Understanding Obstetrical Risk, the risk of rupture in an unscarred mom would be described as “very rare” whereas the risk of rupture in a scarred mom would be described as “uncommon.”

Take away messages

Just because two numbers are less than 1% does not mean that they are similar.  Numbers below 1% represent just as much of a range as numbers greater than 1%.

While the risk of scar rupture is very different than the risk of unscarred rupture, it is similar to other serious obstetrical emergencies such as placental abruption, cord prolapse, and postpartum hemorrhage.
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* Zwart (2009) differentiated between uterine rupture and dehiscence, featured 358,874 total deliveries, 25,989 of which were trials of labor after a cesarean.  Zwart included 97% of births in The Netherlands between August 1, 2004 and August 1, 2006, making it “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country.”

Zwart, J. J., Richters, J. M., Ory, F., de Vries, J., Bloemenkamp, K., & van Roosmalen, J. (2009, July). Uterine rupture in the Netherlands: a nationwide population-based cohort study. BJOG: An International Journal of Obstetrics and Gynaecology, 116(8), pp. 1069-1080. Retrieved January 15, 2012, from http://onlinelibrary.wiley.com/doi/10.1111/j.1471-0528.2009.02136.x/full

Myth: VBACs should never be induced

Note: When I refer to a spontaneous labor, I mean a non-induced/augmented labor. Also, given that the risk of rupture increases with induction, a hospital is the best location for an induction.

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Many of the comments left at the Forced Cesarean mom story questioned the safety of inducing a VBAC mom. Many people believe that is it excessively dangerous and that VBACs should never been induced or augmented. This is just not the case.

Spontaneous labor is always preferable to induced or augmented labor but there are medical conditions that can necessitate the immediate birth of a baby. It’s nice for those women for whom vaginal birth is still an option to have a choice: gentle induction/ augmentation or repeat cesarean. Of course, reviewing the risks and benefits of available options, including doing nothing, is essential. Some women might be more comfortable scheduling a cesarean whereas others might want to give a gentle Pitocin and/or Foley catheter induction a go.

ACOG’s stance on inducing VBACs

The latest 2010 VBAC Practice Bulletin No. 115 produced by the American Congress of Obstetricians & Gynecologists (ACOG) asserts:

Induction of labor for maternal or fetal indications remains an option in women undergoing TOLAC [trial of labor after cesarean]… However, the potential increased risk of uterine rupture associated with any induction, and the potential decreased possibility of achieving VBAC, should be discussed… Misoprostol [Cytotec] should not be used for third trimester cervical ripening or labor induction in patients who have had a cesarean delivery or major uterine surgery.

Stuart Fischbein MD, a vaginal breech/twins and VBAC supportive Southern California OB, recently shared this on my Facebook page,

According to ACOG, prior low transverse c/section is not a contraindication to induction (other than the use of Misoprostol [Cytotec]) so a Foley balloon or Pitocin may be used safely in these women. The problem arises when a practitioner does not believe in doing inductions on women with prior c/section. Despite the evidence and the ACOG clinical guideline the reality is that many doctors will just not want to deal with it.

“Many doctors will just not want to deal with it” for a variety of reasons including experiencing a recent uterine rupture or lawsuit and pressure from hospital administrators or other OBs in their practice. It’s good to know from the beginning if your care provider is open to a gentle VBAC induction and under what conditions they would recommend induction. (See below for the Mayo Clinic’s reasons for induction.) This is why I suggest asking care providers when you first meet with them: “Under what circumstances would you induce a VBAC?” and “What induction methods do you use?”

Medical reasons for induction

While many women are induced for non-medical reasons, such as being pregnant for 40 weeks and one day, there are many medical conditions where induction is a reasonable option. According to the Mayo Clinic’s article Inducing labor: when to wait, when to induce dated July 23, 2011:

Your health care provider might recommend inducing labor for various reasons, primarily when there’s concern for your health or your baby’s health. For example:

  • You’re approaching two weeks beyond your due date, and labor hasn’t started naturally
  • Your water has broken, but you’re not having contractions
  • There’s an infection in your uterus
  • Your baby has stopped growing at the expected pace
  • There’s not enough amniotic fluid surrounding the baby (oligohydramnios)
  • Your placenta has begun to deteriorate
  • The placenta peels away from the inner wall of the uterus before delivery — either partially or completely (placental abruption)
  • You have a medical condition that might put you or your baby at risk, such as high blood pressure or diabetes

ACOG’s 2009 recommendations on induction lists the following reasons:

  • Abruptio placentae [placental abruption]
  • Chorioamnionitis [infection in your uterus]
  • Fetal demise [baby has passed away]
  • Gestational hypertension
  • Preeclampsia, eclampsia
  • Premature rupture of membranes
  • Postterm pregnancy [after 42 weeks]
  • Maternal medical conditions (eg, diabetes, mellitus, renal [kidney] disease, chronic pulmonary disease, chronic hypertension, antiphospholipid syndrome)
  • Fetal compromise (eg, severe fetal growth restriction, isoimmunization, oligohydramnios)

Big babies & going overdue

ACOG’s latest VBAC Pratice Bulletin No. 115 states that going over 40 weeks or suspecting a “big baby” should not prevent a woman from planning a VBAC. I suggest asking your care provider at your first appointment about what they would recommend doing if you go past 40 weeks, past 42 weeks, or if they believe your baby is large. They may suggest a cesarean, a gentle induction, or they be open to waiting for spontaneous labor. Then you decide how you feel about their answer. If you decide that their answer is not a good fit for you, you can weigh that against the responses of other VBAC supportive care providers in your area.

Uterine rupture rates in induced/augmented labors

There are two primary factors when looking at uterine rupture during an induction: the drug and the dose. Keep in mind that while the risk of rupture generally increases as the dosage increases, two women can respond very differently to the same dose of the same drug. According to JHP Pharmaceuticals, LLC, the manufacturer of Pitocin,

Oxytocin has specific receptors in the myometrium and the receptor concentration increases greatly during pregnancy, reaching a maximum in early labor at term. The response to a given dose of oxytocin is very individualized and depends on the sensitivity of the uterus, which is determined by the oxytocin receptor concentration.

Additionally, they assert that Pitocin should not be used for induction without medical indication:

Elective induction of labor is defined as the initiation of labor in a pregnant individual who has no medical indications for induction. Since the available data are inadequate to evaluate the benefits-to-risks considerations, Pitocin is not indicated for elective induction of labor.

Many women point to the fact that the Pitocin drug insert states, “Except in unusual circumstances, oxytocin should not be administered in the following conditions” and then lists “previous major surgery on the cervix or uterus including cesarean section.” However, a prior cesarean is not listed under contraindications and the drug insert is clear:

The decision [to use Pitocin in a woman with a prior cesarean] can be made only by carefully weighing the potential benefits which oxytocin can provide in a given case against rare but definite potential for the drug to produce hypertonicity or tetanic spasm.

The elevated risk of rupture due to induction has been documented in several studies. Landon (2004) found that spontaneous labors had a 0.4% rate of rupture. That increased 2.5 times for induced labors (1.0%) and 2.25 times for augmented labors (0.9%).

Landon further broke out rupture rates by type of induction:

  • 1.4% (N = 13) with any prostaglandins (with or without oxytocin)
  • 0% with prostaglandins alone
  • 0.9% (n = 15) with no prostaglandins (includes mechanical dilation with a foley catheter with or without oxytocin), and
  • 1.1% (N = 20) with oxytocin alone.

Overall, they found 0.7% of women experienced an uterine rupture with an additional 0.7% experiencing a dehiscence.

Landon (2004) did a great job in providing rates of rupture per drug, but we don’t know the dose used in the induced/ augmented labors that ruptured versus those that didn’t rupture.

ACOG quotes a couple studies in their 2010 VBAC Practice Bulletin (emphasis mine):

One study of 20,095 women who had undergone prior cesarean delivery (81) found a rate of uterine rupture of 0.52% for spontaneous labor, 0.77% for labor induced without prostaglandins, and 2.24% for prostaglandin induced labor. This study was limited by reliance on the International Classification of Diseases, 9th Revision coding for diagnosis of uterine rupture and the inability to determine whether prostaglandin use itself or the context of its use (eg, unfavorable cervix, need for multiple induction agents) was associated with uterine rupture.

In a multicenter study of 33,699 women undergoing TOLAC, augmentation or induction of labor also was associated with an increased risk of uterine rupture compared with spontaneous labor (0.4 % for spontaneous labor, 0.9% for augmented labor, 1.1% for oxytocin alone, and 1.4% for induction with prostaglandins with or without oxytocin) (4). A secondary analysis of 11,778 women from this study with one prior low transverse cesarean delivery showed an increase in uterine rupture only in women undergoing induction who had no prior vaginal delivery (1.5% versus 0.8%, P=.02). Additionally, uterine rupture was no more likely to occur when labor induction was initiated with an unfavorable cervix than with a favorable cervix (91). Another secondary analysis examined the association between maximum oxytocin dose and the risk of uterine rupture (94). They noted a dose response effect with increasing risk of uterine rupture with higher maximum doses of oxytocin. Because studies have not identified a clear threshold for rupture, an upper limit for oxytocin dosing with TOLAC has not been established.

Induced labor is less likely to result in VBAC than spontaneous labor (44, 47, 92, 99). There is some evidence that this is the case regardless of whether the cervix is favorable or unfavorable, although an unfavorable cervix decreases the chance of success to the greatest extent (91, 100, 101). These factors may affect patient and health care provider decisions as they consider the risks and benefits of TOLAC associated with labor induction.

Given the lack of compelling data suggesting increased risk with mechanical dilation and transcervical catheters, such interventions may be an option for TOLAC candidates with an unfavorable cervix.

The Guise 2010 Evidence Report is another excellent resource that reviewed VBAC research published to date. It talks extensively about uterine rupture in induced births on pages 58 – 69 and concluded (emphasis mine):

The strength of evidence on the risk of uterine rupture with pharmacologic IOL [induction of labor] methods was low due to lack of precision in estimates and inconsistency in findings. The overall risk of rupture with any IOL method at term was 1.5 percent [1 in 67] and 1.0 percent [1 in 100] when any GA [gestational age] is considered. Among women with GA greater than 40 weeks, the rate was highest at 3.2 percent [1 in 31]. Evaluation of the evidence on specific methods of IOL reveal that the lowest rate occurs with oxytocin [Pitocin] at 1.1 percent [1 in 91], then PGE2 [prostaglandin E2] at 2 percent [1 in 50], and the highest rate with misoprostol [Cytotec] at 6 percent [1 in 17]. These findings should be interpreted with caution as there was imprecision and inconsistency in the results among these studies. The risk of uterine rupture with mechanical methods of IOL is understudied. Other harms were inadequately reported to make conclusions. Relative to women with spontaneous labor, there was no increase in risk of rupture among those induced at term. However, the available evidence on women with induced labor after 40 weeks GA indicates an increased risk compared with spontaneous labor (risk difference 1.8 percent; 95 percent CI: 0.1 to 3.5 percent). The NNH [number needed to harm] in this group is 56 (for every 56 women greater than 40 weeks GA with IOL during a TOL [trial of labor], one additional rupture will occur compared with having spontaneous labor).

So the bottom line is: more large, good quality studies that control for induction are needed.

What is too risky?

As ACOG (2010) states in their latest Practice Bulletin:

Respect for patient autonomy supports the concept that patients should be allowed to accept increased levels of risk, however, patients should be clearly informed of such potential increase in risk and management alternatives.

I agree and believe that each individual woman has the right to informed consent and, together with her care provider, can make the best decision for her individual situation. I think it’s hard to argue that women seeking VBA2C, home birth, or unassisted birth should have the right to accept the elevated levels of risk that come with those decisions and yet say that the elevated risk that comes with induced VBACs is unacceptable.

Keep in mind that while the risk of rupture is higher in an induced VBAC, the risk is similar to the risk of rupture in a VBA2C (0.9% per Landon 2006). So it’s hard for one to support VBA2C and yet demonize a VBA1C induced for medical indication by saying the risk of rupture is to high.

It is also important to note that 90 out of 91 Pitocin induced TOLACs do not rupture (Landon, 2004 & Guise, 2010). So while the risk is generally higher in induced/ augmented labors, the overall risk is still low and occurs at a rate comparable to other obstetrical emergencies.

Myth: Most ruptures occur in induced/augmented labors

It’s imperative that women seeking VBAC understand that the single factor that increases their risk of uterine rupture the most is their prior cesarean section. And while having your labor induced/augmented does increase your risk of rupture, please do not believe the myth that a spontaneous labor provides complete protection from uterine rupture.

To disprove this myth, I direct you to “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country” which found that most ruptures occur in spontaneous labors (Zwart, 2009). Zwart differentiated between uterine rupture and dehiscence and found (emphasis mine):

of the 208 scarred and unscarred uterine ruptures, 130 (62.5%) occurred during spontaneous labor reflecting 72% of scarred ruptures and 56% of unscarred ruptures.

It is interesting to note that 16% of unscarred ruptures (representing 4 unscarred women) and 9% of scarred ruptures (representing 16 scarred women) happened before the onset of labor (Zwart, 2009).

What I would do

If there was a medical reason for my baby to born (as detailed by the Mayo Clinic above), and it was the difference between a VBAC and a repeat cesarean, and I had a favorable Bishop’s score (download the app), I would consent to a foley catheter and/or low-dose Pitocin induction (not Cytotec or Cervidil).

If I was induced or augmented with Pitocin, I would be comfortable with continuous external fetal monitoring. Some hospitals do offer telemetry which is wireless monitoring giving you more freedom of movement. I’ve even seen telemetry in tube tops (naturally I can’t find a link to it now, if you have a link, can you leave a comment?) and units that can be worn in birth tubs. It’s good to call the hospital beforehand to determine what kind of telemetry monitoring units they offer and to confirm that it’s not lost in a closet.

Final thoughts

There is no doubt that Pitocin is overused in America and often results in unnecessary emergency cesareans. However, it’s important not to cloud the two issues: medically unnecessary inductions and inductions with medical indication. There are situations where induction/ augmentation are reasonable and can give the mom one last option before having a cesarean. Thankfully, a low-dose Pitocin and/or foley catheter induction “remains an option” in women planning a VBAC according to ACOG. I think that is a good thing.

Further reading

The best compilation of VBAC/ERCS research to date

“There is a major misperception that TOLAC [trial of labor after cesarean] is extremely risky” – Mona Lydon-Rochelle PhD, MPH, MS, CNM, March 2010

In terms of VBAC, “your risk is really, really quite low” – George Macones MD, MSCE, March 2010

Both Drs. Macones and Lyndon-Rochelle are medical professionals and researchers who made these statements at the 2010 NIH [National Institutes of Health] VBAC Conference. Now you may think, “Wait a sec. Everything I’ve heard from my family, friends, and medical provider is how risky VBAC is and how cesareans are the conservative, prudent, and safest choice.” Why the discrepancy between the statements of these two prominent care provider researchers and the conventional wisdom prevalent in America?

It’s likely that your family, friends, and even your medical provider are not familiar with the latest and best compilation of VBAC research that was released in March 2010. It’s also possible that they are not familiar with the latest VBAC recommendations published in July 2010 by the American Congress of Obstetricians and Gynecologists (ACOG). Additionally, there are often legal and non-medical factors at play that influence how care providers counsel women on VBAC, including pressure from hospital administrators.

When I come across any VBAC study, I always wonder if it made the cut to be included in the 400 page Guise 2010 Evidence Report that was the basis for the 2010 NIH VBAC Conference. Guise 2010 reviewed each published VBAC study, performed a quality assessment, and assembled an excellent review of the VBAC literature to date:

Quality assessment is an assessment of a study’s internal validity (the study’s ability to measure what it intends to measure). If a study is not conducted properly, the results that they produce are unlikely to represent the truth and thus are worthless (the old adage garbage in garbage out). If however, a study is structurally and analytically sound, then the results are valuable. A systematic review, is intended to evaluate the entire literature and distill those studies which are of the highest possible quality and therefore likely to be sound and defensible to affect practice.

Guise focused on these key questions: “1) a chain of evidence about factors that may influence VBAC, 2) maternal and infant benefits and harms of attempting a VBAC versus an elective repeat cesarean delivery (ERCD), and 3) factors that may influence maternal and infant outcomes.” Ultimately, this 400 page document was distilled into the 48 page VBAC Final Statement produced by the NIH VBAC Conference.

This is wonderful because people who want the big picture, can read the VBAC Final Statement whereas those who want to know the exact figures, how studies were included/excluded, and the strength of the data available, can read the Guise 2010 Evidence Report.

You can get a feel for the topics presented at the NIH VBAC Conference by reading the Programs & Abstracts document. If you want more detail, you can watch the individual presentations. I was there for the three day conference and it was eye opening. I wish more medical professionals and moms were aware of this information as they are excellent resources for anyone looking to learn more about VBAC.

Everyone wants to know the bottom line: what is the risk of death or major injury to mom and baby. Here is an overview of maternal and infant mortality and morbidity per Guise (2010). It’s important to remember that the quality of data relating to perinatal mortality was low to moderate due to the high range of rates reported by the strongest studies conducted thus far. Guise reports the high end of the range when they discuss perinatal mortality which was 6% for all gestational ages and 2.8% when limited to term studies. This is a long way of saying, we still don’t have a good picture of how many babies die due to uterine rupture.

It’s also important to remember that the statistics shared in Guise (2010) are for all VBACs. They include all scar types, women who have had multiple prior cesareans, induced/augmented labors, etc. It would have been helpful if they had broke out the data in these ways as we know we can reduce the risk of rupture (and thus perinatal mortality) through spontaneous labor.

While rare for both TOL [trial of labor after cesarean] and ERCD [elective repeat cesarean delivery], maternal mortality was significantly increased for ERCD at 13.4 per 100,000 versus 3.8 per 100,000 for TOL. The rates of maternal hysterectomy, hemorrhage, and transfusions did not differ significantly between TOL and ERCD. The rate of uterine rupture for all women with prior cesarean is 3 per 1,000 and the risk was significantly increased with TOL (4.7 1,000 versus 0.3 1,000 ERCD). Six percent of uterine ruptures were associated with perinatal death. Perinatal mortality was significantly increased for TOL at 1.3 per 1,000 versus 0.5 per 1,000 for ERCD… VBAC is a reasonable and safe choice for the majority of women with prior cesarean. Moreover, there is emerging evidence of serious harms relating to multiple cesareans… The occurrence of maternal and infant mortality for women with prior cesarean is not significantly elevated when compared with national rates overall of mortality in childbirth. The majority of women who have TOL will have a VBAC, and they and their infants will be healthy. However, there is a minority of women who will suffer serious adverse consequences of both TOL and ERCD. While TOL rates have decreased over the last decade, VBAC rates and adverse outcomes have not changed suggesting that the reduction is not reflecting improved patient selection.

Women are entitled to accurate, honest, and high quality data. They don’t deserve to have the risks exaggerated by an OB who wishes to coerce them into a repeat cesarean nor do they deserve to have risks sugar-coated or minimized by a midwife or birth advocate who may not understand the risk or whose zealous desire for everyone to VBAC clouds their judgement. Sometimes it can be hard to find good data on VBAC which is why I’m so thankful for the 2010 NIH VBAC Conference and all the excellent data that became available to the public as a result. There are real risks and benefits to VBAC and repeat cesarean and once women have access to good data, they can individually choose which set of risks and benefits they want. I think the links I have provided above represents the best data we have to date.

Confusing fact: Only 6% of uterine ruptures are catastrophic

It is important to note that the information shared in Guise (2010), the 400 page Evidence Report on which the 2010 NIH VBAC Conference was based, collected the best data we have available on trial of labor after cesarean.  That said, they reported, “Overall, the strength of evidence on perinatal mortality was low to moderate” due to the wide range of perinatal mortality rates reported by the studies included in the report.  Bottom line: We still don’t have an accurate idea of how deadly uterine rupture is to babies.  This is a topic on which Guise recommended future researchers focus.  I highly recommend that anyone interested in TOLAC (trial of labor after cesarean), especially those who blog or share information on social networking sites, review this very important document as it is a fascinating analysis of the best research we have to date on TOLAC.


How many times have you heard, “Only 6% of uterine ruptures are catastrophic” or “Uterine rupture not only happens less that one percent of the time, but the vast majority of ruptures are non-catastrophic?” But what does that mean? Does that mean only 6% of uterine ruptures are “complete” ruptures? Result in maternal death? Infant death? Serious injury to mom or baby? This article will explain to you the difference between uterine rupture and uterine dehiscence as well as explain the source and meaning of the 6% statistic.

Distinguishing between uterine rupture and uterine dehiscence

First, it’s important to understand what a uterine rupture is and how that differs from a uterine dehiscence. Uterine rupture, also called true, complete, or even (to further add to the confusion) catastrophic rupture, is a opening through all the layers of the uterus. Per a Medscape article on Uterine Rupture in Pregnancy:

Uterine rupture is defined as a full-thickness separation of the uterine wall and the overlying serosa. Uterine rupture is associated with (1) clinically significant uterine bleeding; (2) fetal distress; (3) expulsion or protrusion of the fetus, placenta, or both into the abdominal cavity; and (4) the need for prompt cesarean delivery and uterine repair or hysterectomy.

Whereas a uterine dehiscence, also called a incomplete rupture or a uterine window, is not a full-thickness separation. It’s often asymptomatic, does not pose any risk to mom or baby, and does not require repair. Again, I refer to Medscape:

Uterine scar dehiscence is a more common event that seldom results in major maternal or fetal complications. By definition, uterine scar dehiscence constitutes separation of a preexisting scar that does not disrupt the overlying visceral peritoneum (uterine serosa) and that does not significantly bleed from its edges. In addition, the fetus, placenta, and umbilical cord must be contained within the uterine cavity, without a need for cesarean delivery due to fetal distress.

When reading medical studies, look for how they define uterine rupture in the “Methods” section. While some medical studies combine the statistics for rupture and dehiscence, ultimately reporting an inflated rate of rupture, other studies distinguish between the two events.

So, what does the 6% statistic mean and where did it come from?

The statistic “Only 6% of uterine ruptures are catastrophic” is from the Evidence Report (Guise 2010) which was the basis of the 2010 NIH VBAC Conference and it refers to the rate of infant death due to uterine rupture. Here is the exact quote:

The overall risk of perinatal death due to uterine rupture was 6.2 percent. The two studies of women delivering at term that reported perinatal death rates report that 0 to 2.8 percent of all uterine ruptures resulted in a perinatal death (Guise 2010).

In other words, of the women who had uterine ruptures, 6.2% (1 in 16) resulted in infant deaths. When we limited the data to women delivering at term, as opposed to babies of all gestational ages, the risk was as high as 2.8 (1 in 36)%.

When we look at the overall risk of an infant death during a trial of labor after cesarean, the NIH reported the rate of 0.13%, which works out to be one infant death per 769 trials of labor.

The source of the confusion

The problem with this statistic is that some people have misinterpreted it to mean that only 6% of ruptures are true, complete uterine ruptures. In other words, if we take the 0.4% (1 in 240) uterine rupture rate (Landon, 2004), they believe that only 6% of those ruptures or 0.024% (1 in 4166) are true, complete ruptures. This is false. The 0.4% uterine rupture statistic measured true, complete, uterine ruptures in spontaneous labors after one prior low, transverse (“bikini cut”) cesarean.

So how many dehiscences did Landon (2004) detect? Landon reported a 0.7% uterine rupture rate and a 0.7% dehiscence rate. (Note that these statistics include a variety of scar types as well spontaneous, augmented, and induced labors.) So Landon found that dehiscence occurs at the same rate as uterine rupture.

I think the best way to avoid confusion is to use very clear language: 6.2% (1 in 16) of uterine ruptures result in an infant death. Put another way, for every 16 uterine ruptures, there will be one baby that dies.

Elapsed time and infant death

What determines if a baby dies or has brain damage? Some research on infant cord blood gases has suggested that if the baby isn’t delivered (almost always by CS) within 16 – 17 minutes of a uterine rupture, there can be serious brain damage or death to baby. You can watch a presentation from the 2010 NIH VBAC Conference entitled “The Immediately Available Physician Standard” by Howard Minkoff, M.D. for more information or read his presentation abstract.

Now you know the difference between uterine rupture, uterine dehiscence and the meaning of the 6% statistic. It’s helpful to understand the terminology used in relation to uterine rupture otherwise it can be very confusing as you wade your way through the statistics! It’s also very important for people to use specific words whose definitions are clear instead of words such as “catastrophic” that could mean multiple things.

Afterward – The big picture

The following are excerpts from the Evidence Report (Guise 2010) , the 400 page evidence report assembled for the 2010 NIH VBAC Conference. The limitation of Guise (2010) is that these stats are for all VBACs – all scar types, multiple prior cesareans, induced/augmented labors, etc. It would have been helpful if they had broke out the data in these ways.

While rare for both TOL [trial of labor] and ERCD [elective repeat cesarean delivery], maternal mortality was significantly increased for ERCD at 13.4 per 100,000 versus 3.8 per 100,000 for TOL. The rates of maternal hysterectomy, hemorrhage, and transfusions did not differ significantly between TOL and ERCD. The rate of uterine rupture for all women with prior cesarean is 3 per 1,000 and the risk was significantly increased with TOL (4.7 1,000 versus 0.3 1,000 ERCD). Six percent of uterine ruptures were associated with perinatal death.” Perinatal death due to UR from term studies was 2.8%. “Perinatal mortality was significantly increased for TOL at 1.3 per 1,000 versus 0.5 per 1,000 for ERCD… VBAC is a reasonable and safe choice for the majority of women with prior cesarean. Moreover, there is emerging evidence of serious harms relating to multiple cesareans… The occurrence of maternal and infant mortality for women with prior cesarean is not significantly elevated when compared with national rates overall of mortality in childbirth. The majority of women who have TOL will have a VBAC, and they and their infants will be healthy. However, there is a minority of women who will suffer serious adverse consequences of both TOL and ERCD. While TOL rates have decreased over the last decade, VBAC rates and adverse outcomes have not changed suggesting that the reduction is not reflecting improved patient selection.

A systematic review strives to be patient-centered and to provide both patients and clinicians with meaningful numbers or estimates so they can make informed decisions. Often, however, the data do not allow a direct estimate to calculate the numbers that people desire such as the number of cesareans needed to avoid one uterine rupture related death. The assumptions that are required to make such estimates from the available data introduce additional uncertainty that cannot be quantified. If we make a simplistic assumption that 6 percent of all uterine ruptures result in perinatal death (as found from the summary estimate), the range of estimated numbers of cesareans needed to be performed to prevent one uterine rupture related perinatal death would be 2,400 from the largest study,204 and 3,900-6,100 from the other three studies of uterine rupture for TOL and ERCD.10, 97, 205 Taken in aggregate, the evidence suggests that the approximate risks and benefits that would be expected for a hypothetical group of 100,000 women at term gestational age (GA) who plan VBAC rather than ERCD include: 10 fewer maternal deaths, 650 additional uterine ruptures, and 50 additional neonatal deaths. Additionally, it is important to consider the morbidity in future pregnancies that would be averted from multiple cesareans particularly in association with placental abnormalities.

A father says, Why invite the risk of VBAC?

I recently had an exchange with a father that I wanted to share because I think he has the same concerns as many other parents.

He first left a comment in response to the article I’m pregnant and want a VBAC, what do I do?

Make sure they have a surgical team ready to go 24-7 If you are attempting VBAC’S.

They have about 15 min’s to get the child out, without serious damage after complete uterine rupture. It won’t be a Bikini cut either.

I replied:

Anthony,

VBACs can absolutely be offered safely without 24/7 anesthesia present.  I had the opportunity to attend the March 2010 National Institutes of Health VBAC Conference where the ability of rural hospitals to safely attend VBACs was extensively discussed. One doctor spoke during the public comment period and stated that her rural hospital had a VBAC rate of over 30%! It turns out, if a hospital is supportive of VBAC and motivated, they can absolutely offer VBAC safely. (I also welcome you to read the commentary of two obstetricians and one certified nurse midwife who argued against the VBAC ban instated at their local rural hospital.) Read more about the policies that this hospital implemented: VBAC Ban Rationale is Irrational.

One large VBAC study found that while the risk of infant death or oxygen deprivation in VBACs was 0.05%, the maternal mortality in repeat cesareans was 0.04% (Landon, 2004). Whose lives do we save? And in fact Henci Goer’s analysis shares with us that the 0.05% rate is inaccurately elevated. In the Landon (2004) study, women whose babies had died before labor were encouraged to VBAC. Those infant deaths were included in the 0.05% figure even though their deaths could not be attributed to a labor after cesarean.

There was an entire lecture at the 2010 National Institutes of Health VBAC Conference about uterine rupture, oxygen deprivation and blood gases. You can find a summary in the Program and Abstracts.

Warmly,

Jen

Then he left a comment in response to the article A letter from a hospital explaining why they banned VBAC:

Well written letter by the physician. VBAC’s are very risky. I’ve lived through the personal horror of a catastrophe. And trust me it was catastrophic. I nearly lost my wife and full term son. My son now lives his life as a quadriplegic with Cerebral Palsy. You can’t convince me it’s worth the risk. Not for the child, not for the mother, not for the family, and not for the doctor and hospital.

Greedy insurance companies thought they could turn profits by forcing VBAC’s on mothers. The doctor’s letter is true to form and his statistics are on the money. If you care about people, mothers, babies, and family, “Don’t push for VBAC’S” do the opposite.

To which I replied:

Anthony,

I am so sorry about your son.  To describe what happened to your son as tragic is a drastic understatement.

I agree that the policies in place during the 90s when insurance companies were pushing VBAC were entirely unsafe. VBAC became required in some places and some women were not given a choice about whether or not to VBAC. This resulted in women with contra-indications to VBAC experiencing bad outcomes. Women in crowded hospitals did not receive good care and had bad outcomes. Women desiring trials of labor after cesareans were induced and had bad outcomes. And all of this resulted in VBAC getting a bad name. “Instead of blaming the overuse of induction, mandatory VBACs regardless of suitability, and mismanagement of labor, doctors began saying that it was actually VBAC that was unsafe.” You can read more on the history of VBAC here.

Fortunately, we know more now about the risks and benefits of VBAC and repeat cesareans than we did in the 90s. Like how rupture rates vary depending on the scar type (Landon, 2004), how the risks of cesareans increase with each surgery (Silver, 2006) and the risk of uterine rupture and other complications decrease after the first VBAC (Mercer, 2008). We know now that inducing increases the risk of uterine rupture (Landon, 2004), but that it is a reasonable option when there is a medical indication.  As the Guise 2010 Evidence Reports asserts,

“While rare for both TOL [trial of labor after cesarean] and ERCD [elective repeat cesarean delivery], maternal mortality was significantly increased for ERCD at 13.4 per 100,000 versus 3.8 per 100,000 for TOL. The rates of maternal hysterectomy, hemorrhage, and transfusions did not differ significantly between TOL and ERCD. The rate of uterine rupture for all women with prior cesarean is 3 per 1,000 and the risk was significantly increased with TOL (4.7 1,000 versus 0.3 1,000 ERCD). Six percent of uterine ruptures were associated with perinatal death. Perinatal mortality was significantly increased for TOL at 1.3 per 1,000 versus 0.5 per 1,000 for ERCD… VBAC is a reasonable and safe choice for the majority of women with prior cesarean. Moreover, there is emerging evidence of serious harms relating to multiple cesareans.”

So neither option is inherently safe or risky. Both offer a different set of risks. I think it’s important for women to understand these risks when considering their options. I wrote a summary here: Nervous About Planning a VBAC.

Once again, I’m so sorry about your son and I thank you for taking the time to leave your comment.

Warmly,

Jen

To which he replied:

Your statistics mean is nowhere near the mean quoted in the doctors letter. This doctor has performed how many births? and participated in many more. He travels around the country lecturing on this subject? His mean is 2.5% not .05%. .05% is risky too. But I believe 2.5% is more likely for for complications with VBAC.

Accidental death from cesarean he pegs at .001%. That’s .00001

To which I replied:

Anthony,

His statistics are wrong. That is why I posted the letter. I wanted to illustrate how important it is to educate yourself because some OBs just don’t know and give incorrect information either because they don’t know any better or because they are actively skewing their information.  Please read my comment on the differences between an OB’s opinion and medical research.

There is not one large study on VBAC that shows a fetal mortality rate of 1 in 200 (0.5%.) Please check out my bibliography. I’ve read all these studies. If you can find a study on VBAC including over 5,000 women, controlling for scar type, induction method and dose that shows an infant mortality rate of 0.5%, I would love to see it.

Warmly,

Jen

To which he replied:

I still agree with the doctor’s letter above. Why invite the risk? and it is way way too risky. How could the liability limits of a midwife, or small hospital possibly cover such a tragedy? Should that be handled by malpractice reform? By allowing our health professionals to be unaccountable? Recovery for even economic loss is nearly impossible today. The liability is tremendous. Childbirth is already risky enough. I agree that induction may be a contributing factor and maybe more research should be done on those drugs and their use. Cervadil was used to induce my wife, and it was contra-indicated at that time in women with a scarred uterus by “the Physicians Desk Reference”; but that didn’t stop it’s use. This catastrophe didn’t happen in a busy hospital. It happened because the hospital and physicians were not prepared to deal with the profound emergency. I see no benefit to anyone, by lobbying for VBAC’S. Thanks for the reply

To which I replied:

Anthony,

There is about a 0.4% risk of having a uterine rupture with one prior low transverse cesarean in a spontaneous labor (meaning you weren’t induced or given Pitocin or other similar drugs during your labor) (Landon, 2004). One would think that with all the hoopla about uterine rupture, that this rate would be significantly higher than other obstetrical complications.

You might be surprised to learn that uterine rupture occurs at a similar rate to other obstetrical complications such as post partum hemorrhage, cord prolapse or placental abruption! And when we look at infant outcomes, there is about a 6% chance of infant death or oxygen deprivation after an uterine rupture (Landon, 2004) compared to the 12% risk of infant death after a placental abruption (Ananth, 1999).

Yet how many first time moms worry their entire pregnancies about placental abruption? How many considered an elective primary cesarean in an attempt to circumvent abruption? How many were offered, or even strongly pressured, to consider an elective cesarean by their friends, family, or OB? How many where made to feel selfish over their desire to plan a vaginal birth in the face of risks such as abruption?

And where are all the lawsuits resulting from the infant deaths as a result of placental abruption? Why aren’t people outraged that all these babies are dying as a result of selfish moms who should have been prudent and had scheduled cesareans to prevent this tragedy? We hold VBAC to such an impossible standard because the tolerance for risk has been reduced to zero.

Moms planning a VBAC are often made to feel that having a repeat cesarean is the most prudent, conservative choice whereas only selfish women who wish to experience vaginal birth plan a VBAC. Only people who do not understand the statistics would make such a bold claim.

The problem is that most people don’t understand the rate of obstetrical complications in a first time mom. Conventional wisdom and rumor does not give your average individual enough information to adequately compare the risks of a primary vaginal birth, repeat vaginal birth, primary cesarean, repeat cesarean, primary VBAC and repeat VBAC. That is why we have medical studies because even doctors, who themselves attend thousands of births over their career, do not control for variables like researchers do. Doctors focus on practicing medicine whereas researchers, who are often medical doctors who still see patients, focus on constructing studies, maintaining records, and controlling for variables. All of this enables researchers to accurately detect and measure the incidence of complications and also identify larger patterns.

One thing we have learned from medical studies is that the risk of infant death during a VBAC attempt is “similar to the risk” of infant death during the labor of a first time mom (Smith, 2002). Should all first time moms have cesareans because their labor is just to risky?

Let’s not forget that while a cesarean could prevent a would-be uterine rupture, placental abruption, or cord prolapse, cesareans themselves introduce many serious risks. In the face of immediate death or damage to mom or baby, these risks are absolutely acceptable. However, when we are performing major abdominal surgery on the other 99.6% of women who will not have a uterine rupture, we are subjecting them to an unnecessary level of risk.

There are several complications that occur during a second scheduled cesarean section at a rate similar to or greater than the risk of uterine rupture during a spontaneous trial of labor after cesarean after one prior low transverse cesarean (0.4%) (Landon 2004). These complications include hysterectomy (0.42%), any blood transfusion (1.53%), a blood transfusion of four or more units (0.48%), maternal intensive care unit admission (0.57%), maternal wound infection (0.94%), and endometritis (2.56%) (Silver, 2006). And while Silver (2006) found that the maternal death rate was “only” 0.07% during a second cesarean, this is 3.5 times higher than the rate of maternal death in a trial of labor after cesarean (0.02%) and 1.4 times higher than the risk of infant death or oxygen deprivation (0.05%) (Landon, 2004.) Keep in mind that all the cesareans included in the Silver (2006) study were scheduled. All the complications noted were a direct result of the surgery, not of any other medical complication.

These are important facts for people to know before they make the judgment of which option is more “risky:” VBAC vs. repeat cesarean. It’s not enough to understand the risks of VBAC, one must also understand the risks of cesarean section. Only then can one see that neither are inherently safe or risky. They both offer a different set of risks. You can read more about the specific risks that cesareans pose in the article The risks of cesarean sections.

Cesareans also have major implications for all future pregnancies and delivery options. The risks of complications increase with each cesarean section which make subsequent pregnancies more precarious which increases the likelihood of a bad outcome for mom or baby. According to Silver (2006), a four year study of up to six repeat cesareans in 30,000 women:

Increased risks of placenta accreta, hysterectomy, transfusion of 4 units or more of packed red blood cells, [bladder injury], bowel injury, urethral injury, ileus [absence of muscular contractions of the intestine which normally move the food through the system], ICU admission, and longer operative time were seen with an increasing number of cesarean deliveries…. After the first cesarean, increased risk of placenta previa, need for postoperative (maternal) ventilator support, and more hospital days were seen with increasing number of cesarean deliveries.

Because the risks of cesarean are so great, they conclude their study with the following statement, “Because serious maternal morbidity increases progressively with increasing number of cesarean deliveries, the number of intended pregnancies should be considered during counseling regarding elective repeat cesarean operation versus a trial of labor and when debating the merits of elective primary cesarean delivery.”

Additionally, scheduled cesarean section puts anyone else who experiences a medical emergency requiring surgery in danger because those operating rooms become unavailable. I wonder how often women with true obstetrical complications requiring immediate cesareans, such as your wife, or non-obstetrical emergencies such as car accident or gunshot victims, have been unable to receive that urgent, time sensitive care due to otherwise healthy moms and healthy babies undergoing scheduled elective repeat cesareans and tying up the operating rooms? With 92% of women having repeat cesareans (Martin, 2006), I’m sure it’s happened, especially in smaller hospitals, many of which only have one or two operating rooms. These routine repeat cesareans impact everyone and it’s only going to get worse.

According to the CDC (Menacker, 2010), “The number of cesarean births increased by 71% from 1996 (797,119) to 2007 (1,367,049) [and] In 2007, approximately 1.4 million women had a cesarean birth, representing 32% of all births, the highest rate ever recorded in the United States and higher than rates in most other industrialized countries.” The latest data from the CDC shows that 92% of women have a repeat cesarean (Martin, 2009).  So with 1.4 million cesareans annually, we can look forward to approximately 1 million repeat cesareans annually in the future.  With primary cesarean rates growing, our repeat cesarean rate will grow, we will witness more of the complications identified by Silver (2006), including more maternal deaths, and more cases of people who really need emergency surgery dying because operating rooms are filled with otherwise healthy moms and healthy babies undergoing scheduled cesareans.

You said, “It happened because the hospital and physicians were not prepared to deal with the profound emergency.” I would gently suggest that the problem was more with your hospital than VBAC. They induced your wife with a drug that was contraindicated in a trial of labor after cesarean and then were unprepared for an obstetrical emergency. If your wife had a placental abruption or a serious complication from a repeat cesarean, it sounds like they would have been just as unprepared. That is an entirely separate issue than whether VBACs are excessively risky.

Thank you again for your comments and I wish you the best.

Warmly,

Jen

A reader asks, Am I making the right choice?

Isha recently left this comment:

I am pregnant and plan on having a VBAC. As my due date gets closer, I get more nervous about it. I hope I am making the right choice in having the VBAC.

Hi Isha!

I too wondered if it was unreasonable to plan a VBAC and that is when I started researching.  I found that learning more about the risks and benefits of VBAC vs. repeat cesarean gave me a lot of peace.  Check out the Quick Facts page for a brief overview and for more information, check out the information made available by the 2010 National Institutes of Health VBAC Conference.

There is about a 0.4% risk of having a uterine rupture with one prior low transverse cesarean in a spontaneous labor (meaning you weren’t induced or given pitocin or other similar drugs during your labor) (Landon, 2004).  One would think that with all the hoopla about uterine rupture, that this rate would be significantly higher than other obstetrical complications.

So I was really surprised to learn that uterine rupture occurs at a similar rate to other obstetrical complications such as shoulder dystocia, cord prolapse or placental abruption!  And when we look at infant outcomes, there is about a 6% chance of infant death or oxygen deprivation after an uterine rupture (Landon, 2004) compared to the 12% risk of infant death after a placental abruption (Ananth, 1999).

Yet how many of us as first time moms worried our entire pregnancies about any of those complications? How many of us considered an elective primary cesarean in an attempt to circumvent them? How many of us were offered, or even strongly pressured, to consider an elective cesarean by our friends, family, or OB?  How many of us where made to feel selfish over our desire to plan a vaginal birth?

Yet moms planning a VBAC are often made to feel that having a repeat cesarean is the most prudent, conservative choice whereas only selfish women who wish to experience vaginal birth plan a VBAC.  Only people who do not understand the statistics would make such a bold claim.

Just looking at the risks of VBAC isn’t enough when considering your options.  One must also consider the risks of a repeat cesarean.

I also suggest reading Another VBAC Consult Misinforms and Scare Tactics vs. Informed Consent for more discussion on how women are subtley, and sometimes not so subtley, coerced into repeat cesareans by their care providers.  Additionally, check out VBAC Ban Rationale is Irrational for why the much often quoted “24/7 anesthesia requirement” doesn’t make laboring women or hospitals safer.

Most people are not aware of these facts and thus rely on the conventional wisdom and persistent rumor that VBAC is so risky and cesareans are so safe. Neither are true. Both have risks and benefits.

But when comparing the risks and benefits, both the American College of Obstetricians and Gynecologists (2010) and the National Institutes of Health (2010) have deemed VBAC a “reasonable option” for “most women” with one prior cesarean and “some women” with two prior cesareans.  Most people don’t know that either.

I hope this information gives you some peace.  While it’s not terribly soothing to learn that there are major, rare complications that can occur with either option, it’s also good to know that VBAC is not an excessively risky choice.

Warmly,

Jen

_________________________________

American College of Obstetricians and Gynecologists. (2010, July 21). Ob-Gyns Issue Less Restrictive VBAC Guidelines. Retrieved July 21, 2010, from ACOG: http://www.acog.org/from_home/publications/press_releases/nr07-21-10-1.cfm

American College of Obstetricians and Gynecologists. (2010). ACOG Practice Bulletin No. 115: Vaginal Birth After Previous Cesarean Delivery. Washington DC.

Ananth, C. V., Berkowitz, G. S., Savitz, D. A., & Lapinski, R. H. (1999). Placental abruption and adverse perinatal outcomes. JAMA , 282 (17), 1646-1651.

Goer, H. (n.d.). When Research is Flawed: The Safety of Planned Vaginal Birth After Cesarean. Retrieved August 23, 2010, from Lamaze International: http://www.lamaze.org/Research/WhenResearchisFlawed/VBACLandon/tabid/175/Default.aspx

Landon, M. B., Hauth, J. C., & Leveno, K. J. (2004). Maternal and Perinatal Outcomes Associated with a Trial of Labor after Prior Cesarean Delivery. The New England Journal of Medicine, 351, 2581-2589.

National Institutes of Health. (2010, June). Final Statement. Retrieved from NIH Consensus Development Conference on Vaginal Birth After Cesarean: New Insights: http://consensus.nih.gov/2010/vbacstatement.htm

Lightning strikes, shark bites & uterine rupture

When someone understates the risk of UR, I think it’s just as important the clarify as it is when someone overstates the risk. How else are women to make an informed decision? Just as it’s plain wrong for an OB to tell a woman with one prior low transverse cesarean that she has a 20% risk of rupture, it’s equally wrong when VBAC advocates say the risk is virtually non-existent.

Over the years, I have heard the statement: “You are more likely to be struck by lightning or bitten by a shark than experience uterine rupture!”

Today I’m going to get the statistics and run the numbers so you can see for yourself how the risk of these events compare.

Uterine Rupture

For this exercise, we will use the uterine rupture (UR) rate based on one prior low transverse (bikini) cut cesarean in a spontaneous labor determined by Maternal and Perinatal Outcomes Associated with a Trial of Labor after Prior Cesarean Delivery (Landon 2004):

Risk of uterine rupture: 1/240 or 0.4%
Risk of infant death or oxygen deprivation: 1/2000 or 0.05%

Lightning Strikes

Using the faulty theory I’m going to calculate the number of Floridians, since it is the “lightning strike state,” who would be struck by lightning.

Let’s assume that the risk of getting struck by lightning in Florida is the same as uterine rupture (even though the saying goes the risk is greater): 1 in 240 or 0.4%.

With 18,328,340 people living in Florida, that would mean that 76,368 people are struck by lightning every year in Florida. According to the CDC, that is more than the number of Americans who die annually from diabetes (72,449), Alzheimer’s disease (72,432), and influenza and pneumonia (56,326).

Using the National Weather Service stat that 10% of people struck by lightning die, we would have 7,636 people dying in Florida every year from lightning strikes. At that rate, you would have 209 people struck by lightning and 20 of those people dying every day in the state of Florida.

Now, I don’t live in Florida and I’m not an expert in lightning strikes, but that sounds like a lot of people dying.

Now let’s switch our assumptions and use the National Weather Service’s stats.

Odds of being struck by lightning in a given year (reported deaths + injuries) 1/700,000
Odds of being struck by lightning in a given year (estimated total deaths + injuries) 1/400,000

When we turn that fraction into a percentage, we get the following risk of being struck by lightening: 0.00025% – 0.00014%.

Using the National Weather Service’s statistics, we get 26 – 46 annual lightning strike related deaths or injuries in Florida.

Which sounds more reasonable to you? 26-46 Floridians struck annually by lightning or 76,368?

And that is assuming that the rate is the SAME as uterine rupture, but the rumor is that the rate of lightning strikes is HIGHER which means MORE than 76,368 Floridians are struck by lightning every year and more than 20 Floridians are dying daily from lightning strikes.

Now, does that pass the smell test? Does it seem reasonable in the least? It doesn’t to me.

Some would argue that in order to make the comparison, we need to eliminate the number of non-birthing people in Florida, but you really don’t because the lightning strike doesn’t know whether you are a man, woman, child, or menopausal. A Floridian women with one prior cesarean in spontaneous labor has the same risk as everyone else to be struck by lightning: 0.00025% – 0.00014%.

Shark Bites

From the Florida Museum of Natural History:

What are the chances of being attacked by a shark?

The chances of being attacked by a shark are very small compared to other animal attacks, natural disasters, and ocean-side dangers. Many more people drown in the ocean every year than are bitten by sharks. The few attacks that occur every year are an excellent indication that sharks do not feed on humans and that most attacks are simply due to mistaken identity. For more information on the relative risk of shark attacks to humans click HERE.

How many people are attacked each year by sharks?

Worldwide there is an average of 50-70 shark attacks every year. The number of attacks has been increasing over the decades as a result of increased human populations and the use of the oceans for recreational activity. As long as humans continue to enter the sharks’ environment, there will be shark attacks. For more information on shark attack statistics click HERE.

We have about 6.5 billion people on the world and 50-70 get bit by a shark annually which works out to 0.00000077% – 0.00000108%.

But this whole discussion is moot because it’s poor statistics to even compare these events (UR & lightning strikes or shark bites) because they are totally different types of occurrences.

The Actual Figures

This is a great chart from the Floria Museum of Natural History website entitled “A Comparison of Unprovoked Shark Attacks with the Number of Lightning Fatalities in Coastal United States: 1959-2008” where they show even in the state of Florida, over the past 49 years, there have been a mere 453 lightning fatalities and 585 shark bites. Remember that over 7,600 Floridans would be dying annually if the rate of uterine rupture was the same as the rate of lightning strikes.

Comparing Risks

There are some major problems when one is trying to compare risks of differing events.

One problem is when one uses a lifetime risk statistic as a means for comparison. You simply cannot take a statistic, like your lifetime risk of being struck by lightning (1 in 5000 which is significantly lower than one’s annual risk,) and compare that to your one-time risk of uterine rupture. If anything, using the annual risk of lightning strikes would be more accurate, but it still would be a false comparison.

An article by Andrew Pleasant entitled, Communicating statistics and risk, elaborates:

An oft-reported estimate is the lifetime breast cancer rate among women. This rate varies around the world from roughly three per cent to over 14 per cent.

In the United States, 12.7 per cent of women will develop breast cancer at some point in their lives. This statistic is often reported as, “one in eight women will get breast cancer”. But many readers will not understand their actual risk from this. For example, over 80 per cent of American women mistakenly believe that one in eight women will be diagnosed with breast cancer each year.

Using the statistic ‘one in eight’ makes a strong headline but can dramatically misrepresent individual breast cancer risk.

Throughout her life, a woman’s actual risk of breast cancer varies for many reasons, and is rarely ever actually one in eight. For instance, in the United States 0.43 per cent of women aged 30–39 (1 in 233) are diagnosed with breast cancer. In women aged 60–69, the rate is 3.65 per cent (1 in 27).

Journalists may report only the aggregate lifetime risk of one in eight because they are short of space. But such reporting incorrectly assumes that readers are uninterested in, or can’t comprehend, the underlying statistics. It is critically important to find a way, through words or graphics, to report as complete a picture as possible.

Take away message: Be extra careful to ensure your readers understand that a general population estimate of risk, exposure or probability may not accurately describe individual situations. Also, provide the important information that explains variation in individual risk. This might include age, diet, literacy level, location, education level, income, race and ethnicity, and a host of other genetic and lifestyle factors.

The second major problem is often the two things you are comparing are so different that the comparison is worthless. Again, I defer to Mr. Pleasant:

Try not to compare unlike risks. For instance, the all-too-often-used comparison ‘you’re more likely to be hit by a bus / have a road accident than to…’ will generally fail to inform people about the risks they are facing because the situations being compared are so different. When people assess risks and make decisions, they usually consider how much control they have over the risk. Driving is a voluntary risk that people feel (correctly or not) that they can control. This is distinctly different from an invisible contamination of a food product or being bitten by a malaria-carrying mosquito.

Comparing the risk of a non-communicable disease, for example diabetes or heart disease, to a communicable disease like HIV/AIDS or leprosy, is similarly inappropriate. The mechanisms of the diseases are different, and the varying social and cultural views of each makes the comparison a risky communication strategy.

Take away message: Compare different risks sparingly and with great caution because you cannot control how your audiences will interpret your use of metaphor.

Going Forward

It can be hard when wading through the (mis)information available on the internet about VBAC, but here are some tips to help you out.

1. Always find the source – If you find some great statistic, but there is no source referenced, be wary.

2. Verify the statistic – If there is a source listed, read through it. If there is no source listed, do a quick Google search. It didn’t take me long at all to find all the statistics in this article and run the math.

3. Leave a comment – If you find something on the internet that doesn’t pass the smell test, leave a comment on the blog or email the author asking for the source.

4. Be careful about forwarding things – There is so much misinformation on the internet, so do your friends a favor and don’t forward them emails or articles unless you have verified the information to be true. That is one way to quickly nip falsehoods in the bud!

For further reading on using statistics, check out, Correlation and Causation:Misuse and Misconception of Statistical Facts and Risk Communication, Risk Statistics, and Risk Comparisons: A Manual for Plant Managers

Uterine rupture risk drops significantly after first VBAC

As we know, the risks of cesareans increase with each surgery which is why family size should be considered when evaluating your post-cesarean birth options. Couple that fact with the results of Mercer (2008) which found that successful VBAC also provides a level of protection to future deliveries.

Mercer found that not only do the risks of uterine rupture, uterine dehiscence and other peripartum complications decrease after the first VBAC, but “VBAC success increased with increasing number of prior VBACs” to rates over 90% for women with two or more prior VBACs.  They also found that while two or more VBACs did not decrease the risk of rupture further (so a scarred mom’s risk of rupture never goes down to the risk of an unscarred mom), it’s important to note that the risk of rupture did not increase with subsequent VBACs as women are sometimes told in an effort to obtain their consent for a repeat cesarean.

 

Mercer, B. M., Gilbert, S., Landon, M. B., & Spong, C. Y. (2008). Labor Outcomes With Increasing Number of Prior Vaginal Births After Cesarean Delivery. Obstetrics & Gynecology , 11, 285-91. Retrieved from http://journals.lww.com/greenjournal/Fulltext/2008/02000/Labor_Outcomes_With_Increasing_Number_of_Prior.6.aspx

 

Two Doctors Encourage Native American Women to VBAC!

Here is another response to the statement dated December 2007 from Hastings Indian Medical Center explaining why they no longer offer VBAC.

Wow is this article amazing for being published in the post-2004 “anti-VBAC per ACOG” era, by two MDs no less! If your OB gives you the third degree about VBAC, you might want to give him a copy of this article. The tide against VBAC might be turning!

Dated February 2008, not only does it openly and explicitly encourage VBAC, but it also:

  • declares VBAC as the “safest option”
  • encourages efforts to “minimize the primary cesarean delivery rate”
  • asserts that cesareans increase the risk of “placenta accreta, increta and percreta” which “may be particularly difficult to address in a rural community hospital setting”
  • puts the high cesarean rate squarely on the shoulders of OBs: “Physician specific practices influence cesarean delivery rates”
  • notes that OB attitudes towards cesareans is the “largest stumbling block” in lowering the rate
  • concludes that, “An important ingredient in reducing cesarean delivery, either in nulliparous or parous women, is to place value on vaginal delivery”
  • supports “labor management strategies to reduce cesarean rates in the Native American population in the Oklahoma Area and nationwide”
  • questions why smaller hospitals state they can’t accommodate VBAC, yet offer maternity services, when there are other emergencies that occur during non-VBAC labors at a greater rate than uterine rupture
  • encourages hospitals to revaluate their policies and support VBAC
  • asserts that VBAC is successful 75% of the time
  • reaffirms that spontaneous VBAC labors are more successful (80.6%) than VBAC labors that are induced (67.4%) or augmented (73.9%)
  • reaffirms that women who are more than 4 centimeters dilated upon admission have greater VBAC success (83.8% vs. 66.8%)
  • found VBAC success can be had among women with “larger babies” (over 4000 grams or 8 lb, 12 oz) (62%) and women who are ‘overdue’ as defined as 41 weeks or more (64.8%).  I would personally take these odds over the 0% chance of VBAC success if you have a scheduled repeat cesarean!

Maybe the pendulum is finally swinging the other way and this will be the beginning of VBAC support for all women.

The emphasis below is mine.  Note that VBAC is referred to as ‘trial of labor after cesarean’ or TOLAC.

Leeman, Larry, MD, MPH and Eve Espey, MD, MPH. “Concern for rising Cesarean rates in Native American populations.” CCC Corner 6.2 (February 2008)

Concern for rising Cesarean rates in Native American populations

By Larry Leeman MD, MPH and Eve Espey MD, MPH

Editorial Note : The following is in response to a Point / Counterpoint discussion of trial of labor after cesarean (TOLAC) in rural hospitals, December CCC Corner*

We appreciate the willingness to engage in discussion about trial of labor after cesarean (TOLAC) availability and the approach to cesarean delivery at W. W. Hastings Hospital. Every facility faces unique factors in the decision to offer TOLAC services. However, we fear that the high total cesarean rate and lack of TOLAC services will ultimately result in worse perinatal outcomes considered from a population level.

Not only is vaginal birth after cesarean (VBAC) highly desired by many women, but it is preferable to a repeat cesarean delivery in certain women, including those with a single cesarean delivery who have had a successful vaginal birth before or after their cesarean delivery. Evidence suggests that such women should be encouraged to have a TOLAC particularly if they plan to have additional children. Given these data, anesthesia staff should be strongly encouraged to change their policy and offer 1 VBAC services in accordance with guidelines similar to those developed in the Northern New England Perinatal Quality Improvement Network (NNEPQIN). Ethically, it is difficult to justify withholding TOLAC when it is the safest option. If services were offered to this group of women, obstetrical and anesthesia staff could develop greater comfort with TOLAC and expand the local eligibility criteria.

Annual cesarean rates at some Indian Health facilities in Oklahoma are > 37% and short term rates over 40%, hence are above the recently published 2006 national rates for the total U.S population (31.1%), the Oklahoma state population (33.3%), and the US Native American population (27.5%) 2 We note that the Native American cesarean rate increased 1.5% from 2005 to 2006, almost double the 0.8% increase for the total US population. The rising cesarean rate is likely a reflection of both rising primary cesarean delivery rates and decreased vaginal birth after cesarean delivery.

Given the limited availability of TOLAC services for women in the Oklahoma service area, efforts should be made to minimize the primary cesarean delivery rate. The decision to lower the threshold for primary cesarean delivery as evidenced by an acceptance of the high rate and an unwillingness to look at physician specific factors will result in higher adverse outcomes in future pregnancies 3, particularly when combined with the lack of TOLAC services. Women in the Hastings area with primary cesareans can be anticipated to have cesareans in all future births placing them at increased risk for placenta accreta, increta and percreta 5. These complications of abnormal placentation may be particularly difficult to address in a rural community hospital setting.

Although Healthy People 2010 does not include a recommendation for the total cesarean rate due to varying patient factors, it recommends that efforts be made to decrease the primary cesarean rate to 15% in women who are giving birth for the first time 6. ACOG similarly recommends that comparative cesarean delivery rates for populations, hospitals, or physicians should be based on the subgroup of nulliparous women with term singleton vertex gestations 7. We would be interested in seeing the rate for this population at those affected facilities in Oklahoma Area.

We worked in at the Gallup Indian Medical Center (GIMC) and Zuni-Ramah Hospitals in the 1990s and continue to work with Native populations in Albuquerque and New Mexico. Our study of the population based CS rate in Zuni-Ramah in the 1990s demonstrated a 7.3% cesarean rate despite an incidence of diabetes and hypertensive disorders well above national rates 8. Physician specific practices influence cesarean delivery rates 9. We believe that the cesarean delivery review initiated at GIMC in the early 1990s was important in identifying factors in patient management that can result in a high cesarean rate.

An important ingredient in reducing cesarean delivery, either in nulliparous or parous women, is to place value on vaginal delivery. The attitude that “None of the physicians in our department are concerned with our cesarean delivery rate” may prove the largest stumbling block in developing strategies more consistent with national goals.

We suggest that the maternity care providers in Hastings present the evidence for improved maternal outcomes in women with prior vaginal delivery to their anesthesia colleagues and make TOLAC available at least for this group of women. Addressing the high total (and presumably) primary cesarean rates will require analysis of the indications and physician specific patterns. Given the increasing evidence for adverse outcomes with multiple repeat cesareans and the limited ability of community hospitals to address problems with placenta accreta, increta and percreta, we support labor management strategies to reduce cesarean rates in the Native American population in the Oklahoma Area and nationwide.

OB/GYN CCC Editorial comment:

An argument for better teamwork: Trial of labor after cesarean in Indian Country

First, I want to thank the leaders of the Indian Health Midwives listserv for raising these important issues, as this discussion was originally begun in the Midwives Corner feature. Though the current discussion revolves around Indian Health facilities, it is reflective of most small rural hospitals and increasingly some larger urban facilities.

Next, the availability of the trial of labor after cesarean option is really a ‘systems’ issue not just a problem confined to midwives or physicians. To decrease the long term morbidity and mortality associated with cesarean rates that now exceed 40%, we need to approach this issue systematically. Specifically, how can we engage our Indian Health administrative staff to foster an environment whereby anesthesia, pediatric, and nursing services work together with the provider staff to decrease excess morbidity in Native women.

Should you offer vaginal birth after cesarean delivery at your facility?

Should your referral facility be offering VBAC?

Let’s put some of the above issues into perspective.

What are just a few of the risks that you should currently handle very well:

Incidence per 100
Shoulder dystocia 0.2 -3.0
Cord Prolapse 0.14 – 0.62
Abruptio placenta, overall 0.4 – 1.3
Abruptio placenta, severe – stillbirth 0.12
Placenta previa, third trimester 0.1 to 0.4
Placenta accreta, overall 0.18
Placenta accreta / previa unscarred 1 – 5
Placenta accreta / previa with 1 Ces Del. 11 to 25
Placenta accreta / previa with 2 Ces 35 to 47
Placenta accreta / previa with > 3 Ces 50 to 67
Post partum hemorrhage 1 – 5
Trauma 7

In all but one of the above cases the incidence of these obstetric emergencies is actually increasing each year.

If you can’t provide VBAC because of the 0.5% risk of uterine rupture, then should your facility be offering intrapartum care at all? [emphasis theirs]

If you work at a facility that can not develop a rapid response for a clinical issue like symptomatic uterine rupture in a VBAC setting, which happens ~0.5 percent of the time, then your facility, should re-evaluate its ability to manage obstetric intrapartum care.

Taken on their own individual merit, most of the above common urgencies and emergencies occur more frequently than 0.5 percent. Taken as an aggregate, the risks above far outweigh the risks of VBAC. Now seeing the above risks, if you feel you need to re-evaluate offering obstetric intrapartum care because the above risks, then please contact me as soon as possible.

For those facilities that feel they are able to continue to offer obstetric intrapartum care within the risk environment above, then I would suggest a program of emergency obstetric drills, pan-ALSO** certification for all nurses and providers, and an ongoing quality assurance.

Each of the last three national Indian Women’s Health and MCH Conferences has devoted significant blocks of lecture time and workshops to improve systems of care and specific content updates. (Link to Meeting Lecture notes below)

Lastly, there seems to be some confusion as some providers at times combine the risk of a TOLAC sequela vs the relative success of a vaginal birth in TOLAC. These are two separate issues that need to be discussed with our patients separately for a fully informed consent.

1.) Success of vaginal delivery

Overall the rate of successful vaginal delivery in TOLAC is actually quite high, often in the range of 75% in the general population, and much higher success rate in the AI/AN population at 85-90% over the years.

A previous successful VBAC is probably the best predictor of future success; about 90 percent of such women deliver vaginally with trial of labor. By comparison, women delivered abdominally for dystocia are least successful, although approximately two-thirds are delivered vaginally.

Among the previous dystocia group, the success rate is higher if cesarean delivery was performed in the latent phase of labor and lower if performed after full dilatation. Within the former group, 79% of women who originally had surgery while still in the latent phase of labor had a successful trial of labor, compared with 61% of patients who had an arrest of dilation in the active phase of labor and 65% of those who had an arrest of descent. (Duff et al Obstet Gynecol 1988 Mar;71 (3 Pt 1):380-4.)

Multivariate logistic regression analysis identified as predictive of TOL success: previous vaginal delivery (OR 3.9; 95% CI 3.6-4.3), previous indication not being dystocia (CPD/FTP) (OR 1.7; 95% CI 1.5-1.8), spontaneous labor (OR 1.6; 95% CI 1.5-1.8), birth weight <4000 g (OR 2.0; 95% CI 1.8-2.3), and Caucasian race (OR 1.8, 95% CI 1.6-1.9) (all P < .001).

The overall TOL success rate in obese women (BMI > or = 30) was lower (68.4%) than in nonobese women (79.6%) (P < .001), and when combined with induction and lack of previous vaginal delivery, successful VBAC occurred in only 44.2% of cases. (Landon et al The MFMU Cesarean Registry: factors affecting the success of trial of labor after previous cesarean delivery. Am J Obstet Gynecol. 2005 Sep;193(3 Pt 2):1016-23. )

The combination of previous cesarean for dystocia, no previous vaginal delivery, and induced labor had a particularly poor prognosis in the Flamm system, e. g., fewer than 50 percent of such women achieved a successful TOL.

A decision analysis model favored TOL if the chance of success was >50 percent and if the desire for additional pregnancies was 10 to 20 percent. (Mankuta et al Am J Obstet Gynecol 2003 Sep;189(3):714-9.)

Trial of labor success rates: obstetrical and historical factors

Characteristic VBAC success, percent Odds ratio (95% CI)
Previous CD indication
Dystocia 63.5 0.34 (0.30-0.37)
NRFWB [nonreassuring fetal well-being] 72.6 0.51 (0.45-0.58)
Other 77.5 0.67 (0.58-0.76)
Malpresentation* 83.8 1.0
Previous vaginal delivery
Yes* 86.6 1.0
No 60.9 0.24 (0.22-0.26)
Previous VBAC
Yes* 86.6 1.0
No 64.4 0.21 (0.19-0.23)
Labor type
Induction 67.4 0.50 (0.45-0.55)
Augmented 73.9 0.68 (0.62-0.75)
Spontaneous 80.6 1.0
Admit cervical dilation
< 4 66.8 0.39 (0.36-0.42)
≥ 4* 83.8 1.0
Birth weight (g)
< 2500 (5.5 lbs) 77.2 1.14 (0.89-1.47)
2500-3999* (5.5 lbs – 8.8 lbs) 74.9 1.0
≥ 4000 (over 8.8 lbs) 62.0 0.55 (0.49-0.61)
Gestational age (week/day)
37 0/7-40 6/7* 75.0 1.0
≥ 41 64.8 0.61 (0.55-0.68)

All overall P values are <.001; for categorical characteristics, only the comparison of birth weight <2500 g to 2500 to 3999 is not significant (P=.33).
CI: confidence interval; CD: cesarean delivery; VBAC: vaginal birth after CD; NRFWB: nonreassuring fetal well-being.
* Women with this characteristic served as the reference group.
Modified from: Landon, MB, Leindecker, S, Spong, CY, et al. Am J Obstet Gynecol 2005; 193:1016.

Flamm scoring system tool

Variable Point value
Age under 40 years 2
Vaginal birth history
Before and after 1st cesarean 4
After 1st cesarean 2
Before 1st cesarean 1
None 0
Reason other than FTP for 1st cesarean 1
Cervical effacement at admission
> 75 percent 2
25 percent – 75 percent 1
< 25 percent
Cervical dilation 4 cm or more at admission 1
Score (percent) VBAC successful
0 to 2 49
3 60
4 67
5 77
6 89
7 93
8 to 10 95

FTP: failure to progress.
Data from: Flamm, BL, Geiger, AM. Obstet Gynecol 1997; 90:907.

2.) Risks:

Numerous risk factors have been cited for uterine rupture during labor in women with a previous CD. However, these risk factors are not consistent across studies, which are generally hampered by small numbers of patients with uterine rupture. Unfortunately, no single factor or combination of risk factors is sufficiently reliable to be clinically useful for prediction of uterine rupture.

Purported risk factors include maternal age greater than 30 years, induction of labor, more than one prior CD, postpartum fever, interdelivery interval less than 18 to 24 months, dysfunctional labor, and one layer uterine closure. Within this framework of incomplete data the New England Perinatal Quality Improvement Network (NNEPQIN) has developed a system to appropriately manage the risks.

Low Risk Patient:

  • 1 prior low transverse cesarean delivery
  • Spontaneous onset labor
  • No need for augmentation
  • No repetitive FHR abnormalities
  • Patients with a prior successful VBAC are especially low risk.
    (However, their risk status escalates the same as other low risk patients)

Medium Risk Patient:

  • Induction of labor
  • Pitocin augmentation
  • 2 or more prior low transverse cesarean deliveries*
  • < 18 months between prior cesarean delivery and current delivery

High Risk Patient:

  • Repetitive non-reassuring FHR abnormalities not responsive to clinical intervention. /li>
  • Bleeding suggestive of abruption
  • 2 hours without cervical change in the active phase despite adequate labor

* NB: ‘Two prior uterine scars and no vaginal deliveries’ is listed as a circumstance under which trial of labor should not be attempted by the American College of Obstetricians and Gynecologists ACOG Practice Bulletin No. 54, ‘Vaginal birth after previous cesarean delivery’.

Here is a suggested management system per NNEPQIN

Low risk

Notify Pediatrics, Anesthesia, and operating room crew of admission
OB/GYN on campus during active phase
Perinatal Guidelines of Care, ACOG, observed

Medium risk

Notify Pediatrics, Anesthesia, and operating room crew of admission
Operating room on campus in active phase or other plan if crew is busy

High risk

OB/GYN, Anesthesia, and Pediatrics available
No other acute care responsibilities
Rapid decision to incision

Please see the Midwives Corner and Oklahoma Perspective, below, for further discussion on this topic. A complete discussion of risk, benefits, and systems issues is available in the Perinatology Corner module: Vaginal Birth after cesarean http://www.ihs.gov/MedicalPrograms/MCH/M/PNC/VB01.cfm

Other Resources:

Vaginal birth after cesarean (VBAC) in rural hospitals Counterpoint: David Gahn, M.D.

http://www.ihs.gov/MedicalPrograms/MCH/M/obgyn1207_Feat.cfm#MidWives

New England Perinatal Quality Improvement Network (NNEPQIN)

http://www.nnepqin.org/

Indian Health Meeting lecture notes

http://www.ihs.gov/MedicalPrograms/MCH/F/lecNotes.cfm

OB Emergency Drills in Indian Country

http://www.ihs.gov/medicalprograms/mch/F/documents/OBEmergDrills.ppt

2007 Indian Health Data Summary (Deliveries, VBAC rates, etc…)

http://www.ihs.gov/MedicalPrograms/MCH/F/documents/DataTally81107.doc

** ALSO = Advanced Life Support in Obstetrics

http://www.aafp.org/online/en/home/cme/aafpcourses/clinicalcourses/also.html

Leeman and Espey References:

1 Cahill AG, Stamilio DM, ADibo AO, Pelpert JF, et al. Is vaginal birth after cesarean (VBAC) or elective repeat cesarean safer in women with a prior vaginal delivery? Am J Obstet Gynecol 2006; 195:1143-7.

2 Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary data for 2006. National vital statistics reports; vol 56 no 7. Hyattsville, MD: National Center for Health Statistics. 2007.

3 Kennare R, Tucker G, Heard A, Chan A. Risks of adverse outcomes in the next birth after a first cesarean delivery. Obstet Gynecol 2007; 109:270-6.

4 Silver RM, Landon MB, Rouse DJ, Leveno KJ, Spong CY, Thom EA, et al. Maternal morbidity associated with multiple repeat cesarean deliveries. Obstet Gynecol 2006;107:1226–32.

5 Getahun D, Oyelese Y, Salihu HM, Ananth CV. Previous cesarean delivery and risks of placenta previa and placental abruption. Obstet Gynecol 2006;107:771–8.

6 U.S. Department of Health and Human Services. Healthy People 2010. 2nd ed. With Understanding and Improving Health and Objectives for Improving Health. 2 vols. Washington, DC: U.S. Government Printing Office, November 2000.

7 American College of Obstetricians and Gynecologists, Task Force on Cesarean Delivery Rates. Evaluation of cesarean delivery. Washington, DC: American College of Obstetricians and Gynecologists, 2000.

8 Leeman L, Leeman R. A Native American community with 7% cesarean delivery rate: Case mix analysis, risk factors and operative indications. Ann Fam Med. 2003;1:36-43.

9 Luthy DA, Malmgren JA, Zingheim RW, Leininger C. Physician contribution to a cesarean delivery risk model. Am J Obstet Gynecol. 2003;188:1579-85

Cahill AG, Stamilio DM, ADibo AO, Pelpert JF, et al. Is vaginal birth after cesarean (VBAC) or elective repeat cesarean safer in women with a prior vaginal delivery? Am J Obstet Gynecol 2006; 195:1143-7.