Category Archives: Birth myths

woman-laboring-hospital

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/

 

Why cesareans are a big deal to you, your wife, and your daughter

surgery-surgical-instrumentsI hear a lot, “What’s the big deal about cesareans? What difference does it really make if you have a cesarean?” Of course, if a cesarean is medically necessary, then the benefits outweigh the risks. But in the absence of a medical reason, the risks of cesareans must be carefully considered.

“Once a cesarean, always a cesarean”

If a woman has a cesarean, she is very likely to only have cesareans for future births. This is because while 45% of American women are interested in the option of VBAC (1), 92% have a repeat cesarean (2). Let me say that another way. Only 8% of women with a prior cesarean successfully VBAC.

One might interpret this statistic to mean that planned VBACs often end in a repeat cesarean. However, VBACs are successful about 75% of the time (3-7). The VBAC rate is so low because of the women interested in VBAC, 57% are unable to find a supportive care provider or hospital (1). And I would argue further that even among the women who have a supportive care provider, those women are so bombarded by fear based misinformation masquerading as caring advice from friends and family, they have no chance.  It is shocking to learn how ill-informed both women planning VBACs and repeat cesareans are about their birth options even upon admission to the hospital.  There is a fundamental gap in our collective wisdom about post-cesarean birth options.

Cesareans make subsequent pregnancies riskier

What’s the big deal, right? Who cares if you have a cesarean without a medical reason?

Forget about the immediate risks to mom and baby that cesareans impose. Just set that all aside for a moment.  Much of the risk associated with cesareans is delayed.  Most people are not aware of the long term issues that can come with cesareans and how these complications impact the safety of future pregnancies, deliveries, and children.

It is a well-established fact that the more cesareans a woman has, the more risky subsequent pregnancies and labors are regardless if the mom plans a VBAC or a repeat cesarean.  This was discussed at great lengths during the 2010 National Institutes of Health VBAC conference and was one of the reasons why ACOG released their less restrictive VBAC guidelines later that same year.

Many moms chose repeat cesareans because they believe cesareans are the prudent, safest choice. The fact that cesareans, of which over 1,000,000 occur in the USA each year, increases the complication rates of future pregnancies is often not disclosed to women during their VBAC consult.

A four year study looking at up to six cesareans in 30,000 women reported a startling number of complications that increased at a statistically significant rate as the prior number of cesareans increased:

The risks of placenta accreta [which has a maternal mortality of 7% and hysterectomy risk of 71%], cystotomy [surgical incision of the urinary bladder], bowel injury, ureteral injury [damage to the ureters – the tubes that connect the kidneys to the bladder in which urine flows – is one of the most serious complications of gynecologic surgery], and ileus [disruption of the normal propulsive gastrointestinal motor activity which can lead to bowel (intestinal) obstructions], the need for postoperative ventilation [this means mom can’t breathe on her own after the surgery], intensive care unit admission [mom is having major complications], hysterectomy, and blood transfusion requiring 4 or more units [mom hemorrhaged], and the duration of operative time [primarily due to adhesions] and hospital stay significantly increased with increasing number of cesarean deliveries (8).

Because the growing likelihood of serious complications that comes with each subsequent cesarean surgery, including uterine rupture, this study concluded,

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 (8).

This is because the risks of placenta accreta and previa in particular increase at a very high rate after multiple cesareans (9).

The largest prospective report of uterine rupture in women without a previous cesarean in a Western country,” concurred:

Ultimately, the best prevention [of uterine rupture] is primary prevention, i.e. reducing the primary caesarean delivery rate. The obstetrician who decides to perform a caesarean has a joint responsibility for the late consequences of that decision, including uterine rupture (10).

“Well, I just plan on having two kids…”

Unfortunately, many women don’t think about these future risks until they are pregnant again. And we all know the great difference between intended and actual family size.

According to the CDC, 49% of American pregnancies are unintentional (11). Thus, these theoretical risks quickly and suddenly become a reality for hundreds of thousands of American women every year. How women birth their current baby has real and well-documented implications and risks for their future pregnancies, children, and health.

VBAC bans and emergency response

In light of these increasing risks, VBAC bans do not make moms safer (12). Hospitals are either prepared for obstetrical complications, like uterine rupture in moms who plan VBACs and placenta accreta, previa, and cesarean hysterectomies among moms who plan repeat cesareans, or they are not. It is hard to understand how hospitals can claim that they are simultaneously capable of an adequate response to cesarean-related complications and yet they are unable or ill-equipped to respond to complications related to vaginal birth after cesarean.  Especially in light of the fact that we know motivated hospitals currently offer VBAC even in the absence of 24/7 anesthesia (13).

A recent Wall Street Journal article discusses how hospitals are trying to create a standard response to obstetrical emergencies:

The CDC is funding programs in a number of states to establish guidelines and protocols for improving safety and preventing injury.  And obstetrics teams are holding drills to train doctors and nurses to rapidly respond to maternal complications. They are using simulated emergencies that include fake blood, robots that mimic physiologic states, and actresses standing in as patients (14).

Because hospitals vary so greatly in their ability to coordinate a expeditious response to urgent situations,

Vivian von Gruenigen, system medical director for women’s health services at Summa Health System in Akron, Ohio, advises that pregnant women discuss personal risks with their doctor and ask hospitals what kind of training delivery teams have to respond in an emergency. ‘People think pregnancy is benign in nature but that isn’t always the case, and women need to be their own advocates,’ Dr. von Gruenigen says.

Impact of VBAC on future births

Counter the increasing risks that come with cesareans to the downstream implications for VBAC. After the first successful VBAC, the future risk of uterine rupture, uterine dehiscence, and other labor related complications significantly decrease (15). Thus, family size must be considered as VBAC is often the safer choice for women planning large families.

Bottom line? I defer to two medical professionals and researchers:

“There is a major misperception that TOLAC [trial of labor after cesarean] is extremely risky” – Mona Lydon-Rochelle PhD, MPH, MS, CNM (16-17).

In terms of VBAC, “your risk is really, really quite low” – George Macones MD, MSCE (16-17).

Women deserve the facts

Women are entitled to accurate, honest data explained in a clear, easy to understand format (18). 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 facts or whose zealous desire for everyone to VBAC clouds their judgement (19-20).

If you would like to get the opinions of actual VBAC supportive medical professionals who support a woman’s right to informed consent, there are several obstetricians and midwives who you can talk to on the VBAC Facts Community.

Take home message

Cesareans are not benign and the more you have, the more risky your future pregnancies become regardless of your preferred mode of delivery.

Almost half of the pregnancies in America are unintentional.

If hospitals can attend to cesarean-related complications, they can attend to VBAC-related complications.

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1. Declercq, E. R., & Sakala, C. (2006). Listening to Mothers II: Reports of the Second National U.S. Survey of Women’s Childbearing Experiences. New York: Childbirth Connection. Retrieved from Childbirth Connection: http://www.childbirthconnection.org/article.asp?ck=10068

2. Osterman, M. J., Martin, J. A., Mathews, T. J., & Hamilton, B. E. (2011, July 27). Expanded Data From the New Birth Certificate, 2008. Retrieved from CDC: National Vital Statistics Reports: http://www.cdc.gov/nchs/data/nvsr/nvsr59/nvsr59_07.pdf

3. Coassolo, K. M., Stamilio, D. M., Pare, E., Peipert, J. F., Stevens, E., Nelson, D., et al. (2005). Safety and Efficacy of Vaginal Birth After Cesarean Attempts at or Beyond 40 Weeks Gestation. Obstetrics & Gynecology, 106, 700-6.

4. Huang, W. H., Nakashima, D. K., Rumney, P. J., Keegan, K. A., & Chan, K. (2002). Interdelivery Interval and the Success of Vaginal Birth After Cesarean Delivery. Obstetrics & Gynecology, 99, 41-44.

5. 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.

6. Landon, M. B., Spong, C. Y., & Tom, E. (2006). Risk of Uterine Rupture With a Trial of Labor in Women with Multiple and Single Prior Cesarean Delivery. Obstetrics & Gynecology, 108, 12-20.

7. Macones, G. A., Cahill, A., Pare, E., Stamilio, D. M., Ratcliffe, S., Stevens, E., et al. (2005). Obstetric outcomes in women with two prior cesarean deliveries: Is vaginal birth after cesarean delivery a viable option? American Journal of Obstetrics and Gynecology, 192, 1223-9.

8. Silver, R. M., Landon, M. B., Rouse, D. J., & Leveno, K. J. (2006). Maternal Morbidity Associated with Multiple Repeat Cesarean Deliveries. Obstetrics & Gynecology, 107, 1226-32.

9. Kamel, J. (2012, Mar 30). Placenta problems in VBAMC/ after multiple repeat cesareans. Retrieved from VBAC Facts: http://vbacfacts.com/2012/03/30/placenta-problems-in-vbamc-after-multiple-repeat-cesareans/

10. 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

11. National Center for Chronic Disease Prevention and Health Promotion, Division of Reproductive Health. (2012, Apr 4). Unintended Pregnancy Prevention. Retrieved from Centers for Disease Control and Prevention: http://www.cdc.gov/reproductivehealth/UnintendedPregnancy/index.htm

12. Kamel, J. (2012, Mar 27). Just kicking the can of risk down the road. Retrieved from VBAC Facts: http://vbacfacts.com/2012/03/27/just-kicking-the-can-of-risk-down-the-road/

13. Kamel, J. (2010, July 22). VBAC ban rationale is irrational. Retrieved from VBAC Facts: http://vbacfacts.com/2010/07/22/vbac-ban-rationale-is-irrational/

14.  Landro, L. (2012, Dec 10). Steep Rise Of Complications In Childbirth Spurs Action. Retrieved from Wall Street Journal: http://online.wsj.com/article/SB10001424127887324339204578171531475181260.html?mod=rss_Health

15. Mercer BM, Gilbert S, Landon MB. et al. Labor Outcomes With Increasing Number of Prior Vaginal Births After Cesarean Delivery. Obstet Gynecol. 2008 Feb;111(2):285-291. Retrieved from: http://journals.lww.com/greenjournal/Fulltext/2008/02000/Labor_Outcomes_With_Increasing_Number_of_Prior.6.aspx

16. NIH Consensus Development Conference. (2010). Vaginal Birth After Cesarean: New Insights. Bethesda, Maryland. Retrieved from http://consensus.nih.gov/2010/vbac.htm

17. Kamel, J. (2012, Apr 11). The best compilation of VBAC research to date. Retrieved from VBAC Facts: http://vbacfacts.com/2012/04/11/best-compilation-of-vbac-research-to-date/

18. 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/

19. Kamel, J. (n.d.). Birth myths. Retrieved from VBAC Facts: http://vbacfacts.com/category/vbac/birth-myths

20. Kamel, J. (n.d.). Scare tactics. Retrieved from VBAC Facts: http://vbacfacts.com/category/vbac/scare-tactics/

evening-primrose-1458681_640

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

Myth: 50% of uterine ruptures occur before labor

Becky recently ask this question:

I read somewhere that the risk of uterine rupture is actually higher during pregnancy than during birth. Does anyone have a source for this?

Becky,

I had heard the same thing many times. However, no one who shared this stat with me could ever cite a study substantiating it. I looked and looked on and off for years and never found it.

Instead, I found “Uterine rupture in the Netherlands: a nationwide population-based cohort study” (Zwart, 2009), “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country.” Zwart differentiated between uterine rupture and dehiscence and included 97% of births in The Netherlands between August 1, 2004 and August 1, 2006. All told, Zwart studied 358,874 total deliveries, 25,989 of which were TOLACs.

I have referenced Zwart before when comparing scarred vs. unscarred rupture rates and scarred vs. induced, unscarred rupture rates. Zwart also included data on pre-labor rupture which I will share with you as well.

Scar rupture before labor

Zwart reported that 9% (1 in 11) of scar ruptures (women with prior cesareans) happened before the onset of labor. When we take 9% of the overall scar rupture rate of 0.64% (1 in 156)*, we get a 0.0576% (1 in 1736) risk of a scar rupture before labor.

Unscarred rupture before labor

Zwart (2009) found 16% (1 in 6.25) of ruptures in women without prior cesareans (unscarred ruptures) occurred before labor and an overall unscarred rupture rate of 0.007% (1 in 14,286)*. When we multiply these two numbers, we get a 0.00112% (1 in 89,286) risk of uterine rupture in an unscarred uteri before labor.

Here is a table comparing the numbers:

Overall UR Rate % of URs that Occur Pre-Labor Pre-Labor UR Rate
Scarred Uteri 0.64% 9% 0.0576%
Unscarred Uteri 0.007% 16% 0.00112%

The war of the studies

Remember, all these stats are based on one study. Other studies might find different rates. However, I think Zwart would have the most accurate rates to date as it is “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country.” This is an important factor because uterine rupture in an unscarred woman is an extremely rare event. We need tens of thousands of women in order to get an accurate number. The fact that Zwart includes over 300,000 unscarred women is huge.

Take home message: The risk of uterine rupture before labor is extremely rare especially for unscarred women.

* This statistic includes non-induced/ augmented, induced, and augmented labors.

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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

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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

Chipping away at the “too posh to push” myth

glamourous-womanSome new research questions the idea that women who are “too posh to push” are responsible for America’s rising cesarean rate. The work of University of Arizona sociologist Louise Roth has been featured in an University of Arizona UA News article dated April 13, 2012.

Watch for Roth’s research which will be “published in the May issue of the sociology journal Social Problems, published by the Society for the Study of Social Problems.”

I’ve highlighted a few passages for those who like to skim.

By Jeff Harrison, University Communications, April 13, 2012

UA sociologist Louise Roth says the increasing number of cesarean deliveries negatively impacts the health of women and their children and health-care costs.

University of Arizona sociologist Louise Roth wonders why women, at least according to news reports, are increasingly opting to give birth by cesarean section, rather than via natural delivery. Stories have focused on better-educated and more well-to-do women having the surgical procedure, a phenomenon dubbed “too posh to push.”

Roth, an associate professor of sociology who is interested in the effects of malpractice and, more generally, on the impact of the organizational environment on maternity care, looked at the data surrounding the issue and found herself totally stumped.

“I’d been reading a lot in the news about how women were choosing to have cesareans, and what I discovered was that women you would expect would have more cesareans – if that story were true – were not the women who were more likely to have them,” Roth said.

“In fact, the women who were most likely to have cesareans were low-education, Black and Hispanic women, which was not what I expected based on the ‘too-posh-to-push’ story. That was the impetus of this paper. I started playing with the data and found this finding that seemed counter-intuitive to me, and so I decided to investigate further.”

The results of her study will be published in the May issue of the sociology journal Social Problems, published by the Society for the Study of Social Problems.

Roth said the disparities in the rates of cesareans are an important issue because the procedure is tied to maternal deaths and the cost of health care. One key issue is understanding the “pervasive racial-ethnic and socioeconomic disparities in maternity care (and) health care more generally, yet there has been little scrutiny of how overuse of cesarean deliveries might be linked to these disparities.

Roth poured through a year’s worth of data, approximately 4 million recorded births in 2006, the most recent year available. Black, Native American, Hispanic and women from lower socio-economic backgrounds were less likely to have needed cesareans or more likely to have medically unnecessary cesareans.

Either scenario has potentially negative outcomes for both the mother and child. While maternal deaths are statistically low, they still are a concern to public health officials – and deaths from c-sections are four times higher than from vaginal births. Likewise, infants born earlier than 36 weeks, whether naturally or via c-section, are at higher risk for respiratory ailments.

What then is driving the increase in surgeries? Roth asked several researchers, including one who studies cesareans, if this trend was because women want them.

“I think the answer is ‘no.’ Women can have different preferences, but those who have the most ability to exercise those preferences seem to exercise them in the direction of avoiding cesareans rather than choosing them,” she said.

What’s more, lack of prenatal care does not seem to be a factor, and Roth noted that women who get more prenatal care are more likely to have cesareans.

There are other confounding issues. Some studies suggest women in a higher socio-economic status are more likely to get cesareans because they are getting more care than would otherwise be warranted. Other literature report that minority women are more likely to get cesareans.

“I have a statistical model where I account for all of those clinical indications. And when we look at the cases where the clinical indications don’t appear to be there, who is more likely to end up with a cesarean delivery?”

“One thing I find is that if you just look at education alone, with rising education, there are more cesareans, which would suggest that it is the more affluent women who are being overtreated,” Roth said.

“But that is because they are older and maternal age is correlated with cesarean delivery. Once you take that into account, you see that education is actually associated with a much lower probability of having a cesarean.”

A woman who is the same age but has less education is actually more likely to have a cesarean delivery, she said.

“There is that confounding effect that if you look at education alone, without accounting for all those other factors, you might think the ‘too-posh-to-push’ story might be correct. But once you look at everything together, you see that it is not. In fact, it’s the opposite. The ‘posh’ women are more likely to avoid the cesarean.

From a public policy standpoint, Roth said the rising number of cesarean deliveries significantly contributes to the high cost of health care, as well as increasing the risks for women in subsequent pregnancies. Insurance companies and Medicade plans pay more for cesarean deliveries. Hospitals are able to charge more for them.

One goal of her research is dispelling the myth that cesarean deliveries have increased are because women are choosing to have them.

“The most recent data, the last two years suggest that the increase is close to a third, so it is very high, and higher than would be clinically recommended. There also are things that suggest that practice patterns are the cause of this, not the choices that women make,” Roth said.

“In a larger way, there hasn’t been that much attention paid on the beginning of life and the unnecessary costs that are incurred at the beginning of life through these practice patterns.

“There is some discussion of end-of-life care, but not that much on maternity care and how the maternity care system could be made more cost-effective and lead to public health improvements. These things have implications, especially in subsequent pregnancies.”

Contact Info
Louise Roth
UA Department of Sociology
520-621-3531
lroth@email.arizona.edu

dad sleeping with baby

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.

Read more about uterine rupture, scare tactics, birth myths, cesarean section, and the steps for planning a VBAC.

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.

myth versus reality

Myth: Risk of uterine rupture doesn’t change much after a cesarean

myth versus reality

1/18/12 – The difference in uterine rupture (UR) rates between unscarred and scarred uteri is significant: 1 in 14,286 in an unscarred uterus and 1 in 156 in a scarred uterus.  Another way to express this is: 0.7 in 10,000 (0.007%) in an unscarred uterus and 64 in 10,000 (0.64%) in a scarred uterus.  This 91 times greater risk does not mean that the risk of UR is so large in a scarred mom, it’s that it’s so very, very small in an unscarred mom.

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I came across a couple different bits of (mis)information the past day that have really concerned me. In both situations, people, one of whom is a certified professional midwife (CPM), give false information regarding how a cesarean affects one’s risk of uterine rupture in future pregnancies.

First, a women with a prior cesarean asks for uterine rupture rates after a cesarean, “preferable one with stats” on Facebook. One woman gives this reply:

… almost all cases the risk of rupture is less than one percent, even after multiple sections, or special scars such as an inverted T. The risk is roughly double what it is for an unscarred uterus, but considering the tiny numbers it doesn’t really make a difference, especially since the vast majority of ruptures are not catastrophic in nature, something that is not differentiated in study results.

(There are several things that are false in this statement, but I’ll save those for another post.) Then later in the day, I came across this comment from a CPM’s website:

Will you do a vaginal birth after cesarean?
Yes. Studies have shown that there isn’t much of a difference in uterine rupture rates in someone that has had a previous cesarean and someone who has never had one. A lot of my clients are VBAC’s or attempted VBAC’s. I am completely comfortable with this.

Both of these representations of uterine rupture after a cesarean are erroneous. It’s especially disturbing that a midwife who is counseling VBAC moms and attending their births at home, is giving her clients grossly incorrect information. The risk of a uterine rupture does much more than double after a cesarean as the risk in an unscarred uterus is infinitesimal in comparison to a scarred uterus.

Comparing the risk of uterine rupture: Prior cesarean vs. no prior cesarean

I started looking around and quickly found Uterine rupture in the Netherlands: a nationwide population-based cohort study (Zwart, 2009) which contains the data I needed to compare the rates of rupture in unscarred vs. scarred uteri. You can read the study in its entirety here.

This study included 358,874 total deliveries, making it “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country.” It also differentiates between uterine rupture and dehiscence which is really important because we want to measure the rate of complete rupture. (Remember how the lady from Facebook made the statement, ” the vast majority of ruptures are not catastrophic in nature, something that is not differentiated in study results.” That portion of her statement was also false.)

Zwart (2009) looked at 25,989 deliveries after a cesarean and found 183 ruptures giving us a 0.64% uterine rupture rate or 64 per 10,000 deliveries. 72% of those ruptures occurred in spontaneous labors. Of the 183 ruptures, 7.7% resulted in infant deaths representing 14 babies dying. This gives us a rate of infant mortality due to uterine rupture after a cesarean of 0.05% or 5 in 10,000 deliveries.

Zwart also looked at 332,885 deliveries with no prior cesarean resulting in 25 ruptures giving us a 0.007% uterine rupture rate or .7 per 10,000 deliveries. 56% of ruptures occurred in spontaneous labors. Of the 25 ruptures, 24% resulted in infant deaths representing 6 babies dying. This gives us a rate of infant mortality due to uterine rupture in an unscarred uterus of 0.0018% or 0.18 in 10,000 deliveries.

This study found that the risk of uterine rupture is 91 times greater in a woman with a prior cesarean vs. a woman without a prior cesarean. Not double, not similar, but 91 times greater.

It is important to note that, “severe maternal and neonatal morbidity and mortality were clearly more often observed among women with an unscarred uterine rupture as compared to uterine scar rupture.” Meaning, if an unscarred mom ruptures, her baby is more likely to die than a scarred mom. We see this when we compare the 24% of unscarred ruptures that resulted in an infant death vs. the 7.7% of scarred ruptures that resulted in an infant death which represents a 3 fold greater risk.

However, due to the fact that uterine rupture occurs more frequently in a scarred uterus, the risk of infant mortality due to uterine rupture after a previous cesarean was 27.8 times greater than the risk of infant mortality after a rupture in an unscarred uterus.

In other words, while ruptures in unscarred uteri are more deadly to infants, more infants die due to ruptures in scarred uteri because they occur more frequently.

OBs are often vilified (rightfully so) for giving women inflated rates of uterine rupture and I’ve documented several examples here: Another VBAC Consult Misinforms, Scare tactics vs. informed consent, Hospital VBAC turned CS due to constant scare tactics, and A father says, Why invite the risk of VBAC?.

As a result, women seek out midwives thinking that they will be a source of accurate information and judicious support. But what happens when your midwife tells you that your risk of uterine rupture has not increased as a result of your prior cesarean section? If you have done your homework, hopefully you find another midwife fast. I would really question the skills and knowledge of a midwife who is so unknowledgeable on the risks of VBAC and yet attends VBAC births in an out-of-hospital setting.

But suppose your haven’t done your homework, you trust your midwife, and you move forward with your plan to have a VBAC at home based on the incorrect statistics she supplies. I can’t begin to imagine the rage I would feel if I decided to have a home VBAC based on false information provided by my care provider, and then the unimaginable happened, and I ruptured, and then I learned the truth: that my risk of uterine rupture increased 91 times as a result of my prior cesarean. I would be beyond angry. I would feel so betrayed.

It’s unfortunate when a woman chooses a mode of delivery based on false information. Whether it’s a a woman deciding to have a repeat cesarean due to the exaggerated risk of uterine rupture provided by her OB or a woman deciding to have a (home) VBAC due to her midwife playing down and underestimating the risk of uterine rupture. It is just as bad to minimize the risk of uterine rupture as it is to inflate the risk.

While the risk of rupture in a spontaneous labor after one prior low transverse cesarean is comparable to other obstetrical emergencies, it is important for women weighting their post-cesarean birth options to know that their risk increased substantially due to their prior cesarean. It is important for them to understand the risks and benefits of VBAC vs. repeat cesarean. It is important for them to have access to accurate information and be able to differentiate between a midwife’s/blogger’s/doula’s/birth advocate’s/person on Facebook’s hopeful opinion vs. documented statistics.

I implore those who interact with, and have impact on, women weighing their birth options: do not pass along information, no matter how great it sounds, if you don’t have a well-designed scientific study supporting it. If you hear a statistic you would love to use and share, just ask the person who gave you this information,”What is the source?” and use the citation anytime you quote the statistic. But if the person doesn’t have a well-designed scientific study, be wary and don’t use the stat. This way, we can reduce the rumor and increase the amount of good information on the Internet. I know, a lofty goal.

Read more birth myths debunked including Lightning strikes, shark bites, and uterine rupture and Myth: Unscarred mom induced (with Pit) as likely as VBAC mom to rupture.

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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

rutpures in scarred uteri

Fact or Myth

Myth: Induced unscarred mom as likely as VBAC mom to rupture

Fact or MythUpdate 1/20/12 – Someone who believed this birth myth to be true, told me that the source of this information was an OB from St. Louis who presented at the 2011 ICAN conference. I contacted ICAN and they said that the person must be referring to Dr. George Macones. Yet, no one on the ICAN Board, who were seated at the front table during his presentation, remembers him saying that induced, unscarred women have the same risk of uterine rupture as a VBAC mom. And I would think that if he gave a stat like, everyone would have remembered because it is quite a remarkable statement as you will see shortly. While many women repeat, believe, and defend this statement, no one has supplied one study to me to support it.

Update 1/21/12 – Ruth S Beattie Dicken, the Speaker Chair of the 2011 ICAN conference contacted me via Facebook and said, ” Dr Macones did not say that. Nor did any other OB. I sat in on every session with OB speakers.”

Update 1/21/12: The difference in uterine rupture (UR) rates between unscarred, induced uteri and scarred uteri is significant: 2.2 per 10,000 in an unscarred, induced uterus and 64 in 10,000 in a scarred uterus. But it’s not that the risk of UR is so large in a scarred mom, it’s that it’s so very, very small in an unscarred mom, even when she is induced.

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OBs are often vilified (rightfully so) for giving women inflated rates of uterine rupture and I’ve documented several examples over the years: Another VBAC Consult Misinforms, Scare tactics vs. informed consent, Hospital VBAC turned CS due to constant scare tactics, and A father says, Why invite the risk of VBAC?. But the midwife (or OB, but it’s generally a midwife) who gives false information that minimizes the risk of rupture is just as harmful to the VBAC mom. Since I wrote Lightning strikes, shark bites, and uterine rupture, I’ve been making mental notes of other birth myths that seem to be forwarded from woman to woman, without anyone asking, “That’s a great statistic! What’s the source?”

There is one that I hear quite often:

A woman without a prior cesarean whose labor is induced is just as likely as a VBAC mom to experience an uterine rupture.

Recently, I heard it again and I really wanted to know if there was some study that demonstrated this. It’s a logical conclusion that inducing an uscarred woman would increase her risk of rupture as uterine rupture is listed as a risk for Pitocin and prostaglandins (such as Cytotec and Cervidil) but how much does induction increase the risk of uterine rupture in an unscarred uterus? And does the rate of rupture increase so much that it is the same as the risk of rupture in a VBAC mom? I had unsuccessfully looked for that information in the past, so I went to my Facebook page and asked if anyone had a source.

Several women responded who had heard this information, two of which from their midwives which is really frightening. Unfortunately, no one who responded could cite where they heard this information. So I started looking and found Uterine rupture in the Netherlands: a nationwide population-based cohort study (Zwart, 2009).

This study included 358,874 total deliveries, making it “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country.” It also differentiates between uterine rupture and dehiscence which is really important because we want to measure the rate of complete rupture. You can read the study in its entirety here.

The role of induction in scarred and unscarred uterine rupture

Zwart utilized multiple methods of induction: cervical prostaglandins (sulproston, dinoproston, and misoprostol aka Cytotec), oxytocin (Pitocin) and mechanical dilatation. Prostaglandin “dosages ranged from 0.5 to 2.0 mg with a minimal interval of 4 h in between,” but they do not provide the dosages of the women who ruptured.

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. 28 (13.5%) ruptures occurred during cervical prostaglandin induction. 22 (10.6%) ruptures occurred during oxytocin (Pitocin) induction.

It seems that there were women who were induced with prostaglandins and Pitocin as measured in Table 5. But there is no measure for women who ruptured and were induced with both prostaglandins and Pitocin in any of the uterine rupture tables.

There is no mention of Bishop’s score, but they did provide the “reasons for induction with prostaglandins [in scarred women which] included (nearly) post-term pregnancy (n = 10), intra uterine fetal death/ multiple congenital abnormalities (n = 5), elective (n = 3), pregnancy induced hypertension (n = 2), intra uterine growth restriction (n = 1) and prelabour rupture of membranes (n = 1).”

Interestingly, this Netherlands-based study found “there was a trend towards more liberal use of prostaglandins for induction of labour in low-volume hospitals as compared to middle- and high-volume hospitals (24.4% versus 13.0% of cases, P = 0.29).”

It’s also interesting that there were no maternal deaths even though “18 [unscarred] women (72%), rupture occurred outside office hours.”

The risk of uterine rupture in an induced labor without a prior cesarean

The study found, ” In 11 women [without a prior cesarean who experienced a uterine rupture], labour was induced, in all but one with prostaglandins.” Said in another way, 40% of the unscarred women who ruptured were induced with prostaglandins versus only 12.1% of scarred moms who ruptured.

So Zwart found that it’s not the Pitocin that causes the ruptures in unscarred moms, it’s the prostaglandins. This is logical because prostaglandins are harder to control. If the uterus is hyper-stimulating due to prostaglandins, they continue to work on the uterus even after they have been removed from the cervix. Pitocin, on the other hand, has a short half-life so the body responds quicker to the drip being turned off in the event of uterine hyper-stimulation.

While we know that there are 332,885 unscarred women included in this study, we don’t know the number or percentage of unscarred women who were induced. We need this information in order to calculate the rate of uterine rupture in induced, unscarred women.

So I did a little looking and I found Verhoeven (2009) which states ” In The Netherlands induction rates have remained stable over the last decades at approximately 15%.” Since the induction rate has been stable, and this study included 97% of births in The Netherlands between August 1, 2004 and August 1, 2006, I feel comfortable using this 15% rate of induction to calculate the rate of uterine rupture in induced, unscarred women.

So when we take 15% of the 332,885 unscarred women in the study, we get 49,933 induced, unscarred women.

Dividing the 11 ruptures that occurred in induced, unscarred women by 49,933 total induced, unscarred women, we get the following uterine rupture rate in induced, unscarred women: 0.022% or 2.2 per 10,000 deliveries.

Now let’s look at the rate of uterine rupture in women with a prior cesarean: “25,989 trials of labor were attempted in the Netherlands during the study [resulting in 183 ruptures.] The risk of uterine rupture would then be 0.64%” or 64 in 10,000 deliveries. This rate includes ruptures in induced and spontaneous labors, but we do know that 72% of those ruptures occurred during spontaneous labors.

In other words, a woman with a prior cesarean section has a uterine rupture risk 29 times greater than the risk of uterine rupture due to induction in a woman without a prior cesarean, 0.64% vs. 0.022%.

Another way to look at the data is: you would need to induce 4,546 women without a prior cesarean in order to get one uterine rupture due to induction.

While I hadn’t seen the numbers until now, I was always very skeptical when I heard this rumor. I’m glad to finally have hard numbers to share.

How does induction affect the rate of uterine rupture in an unscarred woman?

Next, since I had all the data available, I wanted to calculate how induction affects the rate of uterine rupture in an unscarred woman. Remember that 10 of the 11 ruptures in induced, unscarred women occurred during the use of prostaglandins and we don’t have information on the dosage in those labors.

We already established that the rate of rupture in an induced, unscarred labor was 0.022% or 2.2 per 10,000 deliveries.

The remaining 14 ruptures of the 25 total ruptures occurred during spontaneous labor.

14 spontaneous ruptures among 282,952 spontaneous labors in unscarred women, gives us a 0.0049% uterine rupture rate or .49 per 10,000 deliveries.

As I suspected, an unscarred woman induced with prostaglandins has a greater risk of uterine rupture than an unscarred woman in a spontaneous labor, but now we have exact figures: 0.022% vs. 0.0049%. Prostaglandin induction in an unscarred woman increases her risk of uterine rupture almost 5 times, but the overall risk is still extremely low.

Moving forward

It was interesting to note that among women with a prior cesarean, 72% of ruptures occurred during spontaneous labor. The scar itself, that prior cesarean surgery, is what increases the risk of uterine rupture the most. With this in mind, the researchers state:

With 29% of all previous caesareans being performed for breech presentation, we clearly show the negative side effects and long-term adverse consequences of routinely performing elective caesarean for breech delivery . . . the only means of reducing the incidence of uterine rupture is to minimise the number of inductions of labor and to closely monitor women with a uterine scar. . . Ultimately, the best prevention [of uterine rupture] is primary preventions, i.e. reducing the primary cesarean delivery rate. The obstetrician who decides to perform a caesarean has a joint responsibility for the late consequences of that decision, including uterine rupture.

This is why more hospitals offering breech vaginal birth and VBAC, such as Portland, OR based Oregon Health & Science University (OHSU), is so important. Read more about OHSU’s mission to reduce the cesarean rate.

As I say in Myth: Risk of uterine rupture doesn’t change much after a cesarean:

While the risk of rupture in a spontaneous labor after one prior low transverse cesarean is comparable to other obstetrical emergencies, it is important for women weighting their post-cesarean birth options to know that their risk increased substantially due to their prior cesarean. It is important for them to understand the risks and benefits of VBAC vs. repeat cesarean. It is important for them to have access to accurate information and be able to differentiate between a midwife’s/blogger’s/doula’s/birth advocate’s/person on Facebook’s hopeful opinion vs. documented statistics.

I implore those who interact with, and have impact on, women weighing their birth options: do not pass along information, no matter how great it sounds, if you don’t have a well-designed scientific study supporting it. If you hear a statistic you would love to use and share, just ask the person who gave you this information,”What is the source?” and use the citation anytime you quote the statistic. But if the person doesn’t have a well-designed scientific study, be wary and don’t use the stat. This way, we can reduce the rumor and increase the amount of good information on the Internet. I know, a lofty goal.

I use the data in this same study to debunk the myth: the risk of uterine rupture is roughly double, or not much different, from an unscarred uterus. . . more dangerous information from what should be trusted sources.

Read more birth myths debunked including Lightning strikes, shark bites, and uterine rupture and Myth: Risk of uterine rupture doesn’t change much after a cesarean.

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Notes: This study found that there were 183 ruptures after a prior cesarean and states in the abstract that this reflects a rate of 0.051% or 5.1 per 10,000 deliveries. But the problem is, they divided the number of uterine ruptures after a cesarean by the total number of women (with a prior cesarean and without.) It’s only towards the end of the study do they state the risk of uterine rupture in a woman after a prior cesarean is 0.64%. So, this is a little confusing and is another example of why reading the entire study, rather than just the abstract, is so important.

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Verhoeven, C., Oudenaarden, A., Hermus, M., Porath, M. M., Oei, S. G., & Mol, B. (2009). Validation of models that predict Cesarean section after induction of labor. Ultrasound in Obstetrics & Gynecology, 34, pp. 316-321. Retrieved January 15, 2012, from http://onlinelibrary.wiley.com/doi/10.1002/uog.7315/pdf

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

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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% or 0.00416

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