Category Archives: Uterine Rupture

Shoulder pain is a symptom of uterine rupture

I’ve written before about the symptoms of uterine rupture as well as how having an epidural does not interfere with the diagnosis of uterine rupture.

The focus of this Quick Fact is how shoulder pain can be a symptom of uterine rupture.

How can an uterine rupture cause shoulder pain?

Image Source: http://wesleytodd.blogspot.com/2013/10/ablation-for-recurring-af-i.html

Image Source: http://wesleytodd.blogspot.com/2013/10/ablation-for-recurring-af-i.html

Internal bleeding from uterine rupture can cause referred pain through the phrenic nerve which can present in the shoulder.

Shoulder pain is sometimes not included in lists of uterine rupture symptoms, but I have seen it cited multiple places (see below) and have had conversations with OBs, nurses, and anesthesiologists who have experienced uterine ruptures with shoulder pain.

I’m also aware of two cases where the uterine rupture diagnosis was delayed because staff was not familiar with the incidence of referred pain.

Anyone who works with birthing women should be aware of the symptoms of uterine rupture including referred pain.

Please note that not every uterine rupture causes shoulder pain and not all shoulder pain is a symptom of uterine rupture.

Where can you learn more?

I discuss uterine rupture – factors, symptoms, rates, and outcomes – at great lengths in my online workshop, “The Truth About VBAC: History, Politics, & Stats

The following quotes addressing shoulder pain & uterine rupture are from case studies and textbooks. Want more? Google uterine rupture referred pain or uterine rupture shoulder pain.

“APH [brisk antepartum haemorrhage], as in this case, often indicates uterine rupture and may occur in association with shoulder tip pain due to haemoperitoneum.” (Navaratnam, 2011)

“Management of uterine rupture depends on prompt detection and diagnosis. The classic signs (sudden tearing uterine pain, vaginal haemorrhage, cessation of uterine contractions, regression of the fetus) have been shown to be unreliable and frequently absent but any of the following should alert suspicion… Chest or shoulder tip pain and sudden shortness of breath.” (Payne, 2015)

“Signs and symptoms of uterine rupture may include… referred pain in the shoulder (with epidural anesthesia)” (Murry, 2007 p.283)

“Jaw, neck, or shoulder pain can be referred pain from a uterine rupture.” (Murry, 2007, p.76)

“Shoulder pain (Kehr’s sign) is a valuable sign of intraperitoneal blood in subdiaphragmatic region. Even a small amount of blood can cause this symptom, but it is important to realize that it may be 24 h or longer after the bleeding has occurred before blood will track up under the diaphragm, and some cases of acute massive intraperitoneal bleeding may not initially have shoulder pain.” (Augustin, 2014, p. 512)

“Shoulder tip pain may be experienced if significant haemoperitoneum is present, due to irritation of the diaphragm (i.e. referred pain through phrenic nerve).” (Baker, 2015, p.373)

References

Augustin, G. (2014). Acute abdomen during pregnancy. Switzerland: Springer International Publishing. Retrieved from https://books.google.com/books?id=mq8pBAAAQBAJ

Baker, P. N., McEwan, A. S., Arulkumaran, S., Datta, S. T., Mahmood, T. A., Reid, F., . . . Aiken, C. (2015). Obstetrics: Prepare for the MRCOG: Key articles from the Obstetrics, Gynaecology & Reproductive Medicine journal. Elsevier Ltd. Retrieved from https://books.google.com/books?id=DcqqCgAAQBAJ

Murray, M. (2007). Antepartal and intrapartal fetal monitor. New York, NY: Springer Publishing Company, LLC. Retrieved from https://books.google.com/books?id=_4jYJUGG56cC

Murray, M., & Huelsmann, G. (2008). Labor and delivery nursing: Guide to evidence-based practice. New York, NY: Springer Publishing Company. Retrieved from https://books.google.com/books?id=q22jEEZo7rwC

Navaratnam, K., Ulaganathan, P., Akhtar, M. A., Sharma, S. D., & Davies, M. G. (2011). Posterior uterine rupture causing fetal expulsion into the abdominal cavity: A rare case of neonatal survival. Case Reports in Obstetrics and Gynecology, 2011. Retrieved from http://www.hindawi.com/journals/criog/2011/426127/

Payne, J. (Ed.). (2015, Mar 17). Uterine rupture. Retrieved from Patient: http://patient.info/doctor/Uterine-Rupture

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Q&A: VBAC after a uterine rupture?

Pregnant GirlI apologize for not writing in so long. I’ve been busy with various projects including producing my 6 hour program “The Truth About VBAC” to be released online this summer! Subscribe to my newsletter to be informed of this and future classes!

I’ve been responding to many questions over on my Facebook page and have been trying to think of ways to archive those discussions here for future reference. Then the obvious answer appeared… post the questions and answers here and link back to the original question posted on Facebook! So, here we go! I look forward to blogging more in the future!

Question: “Any research on TOLAC or VBAC after a uterine rupture?”

The only research I’m aware of is cited by the latest ACOG guidelines. But let’s take one step back… before even looking at the research, I would clarify if the event was a dehiscence or a uterine rupture (UR). Read more about these two events here.

I recommend getting a copy of your medical records/operative report to confirm what exactly happened and review them with a VBAC supportive care provider. Here are steps on how to find a VBAC supportive provider and what questions to ask.

According to ACOG’s 2010 VBAC guidelines, women who have had a uterine rupture are not candidates for VBAC:

How should future pregnancies be managed after uterine rupture? If the site of the ruptured scar is confined to the lower segment of the uterus, the rate of repeat rupture or dehiscence in labor is 6% (117). If the scar includes the upper segment of the uterus, the repeat rupture rate has been reported to be as high as 32% (117, 118). Given both these rates, it is recommended that women who have had a previous uterine rupture should give birth by repeat cesarean delivery before the onset of labor. Because spontaneous labor is unpredictable and could occur before the recommended 39 weeks for an elective delivery, earlier delivery should be contemplated with consideration given to amniocentesis to document fetal lung maturity.

ACOG’s sources are very old:

117. Ritchie EH. Pregnancy after rupture of the pregnant uterus. A report of 36 pregnancies and a study of cases reported since 1932. J Obstet Gynaecol Br Commonw 1971;78:642–8. (Level III)

118. Reyes-Ceja L, Cabrera R, Insfran E, Herrera-Lasso F. Pregnancy following previous uterine rupture. Study of 19 patients. Obstet Gynecol 1969;34:387–9. (Level III)

Since the limited evidence indicates a high risk of rupture, it would be unethical to further study it and subject women to this increased risk simply to pinpoint the exact rate of uterine rupture after uterine rupture.

Fundamentally, the uterus is rupturing because something is not quite right: whether that is damage from a prior cesarean, a defect, a fluke or over-stimulation from induction/ augmentation drugs. A uterus will carry the cause (damage, defect, fluke) and the damage of the rupture into the next pregnancy. This weakens the integrity of the uterus and increases the rupture risk in subsequent labors. This risk is even higher if the rupture occurs in the upper part of the uterus called the fundus. This is because the fundus does all the work during labor.

Some people equate the uterine incision during a cesarean with the uterine opening during a uterine rupture. They say that scheduling a cesarean results in a “100% risk of rupture.” But this is a false comparison because during a rupture, the uterus is opening because something is not working correctly. With a cesarean, the uterus is opening as a result of surgery. The rupture can tear across major blood vessels and/or where the placenta is implanted causing major bleeding in the mother and oxygen deprivation in the baby. The cesarean is a controlled cut that seeks to avoid any major blood vessels and the placenta. This is an entirely different event than a uterine rupture and it’s disingenuous to compare the two.

I’ve heard others say that it’s better to let the uterus “rip naturally” during a uterine rupture equating the controlled cut of a cesarean to that of a routine episiotomy. The structure and function of the vagina is very different than the uterus as well as the cause of vaginal versus uterine tears. The maternal and infant morbidity and mortality rates for uterine rupture are higher than those associated with a vaginal tear. It’s another false comparison.

I’d also like to add that I’ve never read any studies on pregnancy or labor after a dehiscence. It could be out there, but they are unlikely to be large enough to be meaningful since most dehiscences are diagnosed at surgery or by manual examination after vaginal birth (which ACOG does not recommend), so (it’s assumed) that many (most?) are missed. Opinions on pregnancy or labor after a dehiscence vary by health care provider.

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

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

False comparison: Fatal car accidents (or other non-birth risks) and VBAC

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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?

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The best compilation of VBAC/ERCS research to date

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

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

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

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

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

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

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

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

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

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

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

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

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

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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.

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

entirety

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Time management

Birth intervals & uterine rupture aka how long to wait to VBAC

Suzanne recently left this comment in response to the article, I’m pregnant and want a VBAC, what do I do?

Hi. I’m new to your site and just trying to get some more info on VBAC. My daughter was a normal vaginal delivery. My second pregnancy(a surrogate pregnancy) was also a normal vaginal delivery. My third (also a surrogate pregnancy) was twins. I had planned to attempt a vaginal delivery with the twins with the support of my OB as long as Baby A was head down. Unfortunately she was breech and I ended up with a c-section at 36 1/2 weeks. My OB said if I want to attempt a VBAC for my next pregnancy I need to wait at least 2 years between the c-section and getting pregnant again. Is she just being cautious? Or is it really necessary to wait 2 years?

Suzanne,

I cover interbirth intervals in great detail in my class.  Here is a brief summary.

The short answer is: The range 18 – 24 months between pregnancies (delivery to conception) is the general recommended interval regardless of mode of delivery. It’s not just about the physical recovery from delivery (vaginal or cesarean.) It’s about the general stress and strain on our bodies/minds from the pregnancy, delivery, breastfeeding, and then caring for an infant.

Pregnancies that are to close together, or to far apart, are associated with higher complication rates. WebMD mentions 18 months from delivery to conception and the MayoClinic mentions 12 months.

Speaking specifically of VBACs, the concern mentioned is a possible increase of uterine rupture.  ACOG’s VBAC guidelines associate short birth intervals with lower VBAC rates, but they do not mention a connection between short birth intervals and increased rates of uterine rupture.  That is because the studies that ACOG cites include insufficient sample sizes and/or high rates of induction and augmentation.

Stamilio (2007) found the rate of uterine rupture when women got pregnant less than 6 months after their cesarean to be 3.05%, which was three times higher than their average rate of 0.9%. That is a very high rate of rupture, but keep in mind two things.

First, they only had 286 women who got pregnant within 6 months of their cesarean and that is not a large enough population to measure uterine rupture which occurs about 0.4% of the time in spontaneous labors after one prior low transverse cesarean (Landon, 2004).   In order to accurately measure something that happens at that rate, we need about 5,000 women for that one category.

Second, 68% of those 286 women had their labors induced or augmented which we know increases the risk of rupture (Landon, 2004).

Stamilio (2007) stated [emphasis mine], “We hypothesized that short interpregnancy intervals may lead to altered wound healing and an increased risk of uterine rupture in patients who attempt a vaginal birth after cesarean. Our hypothesis is based on previous observational studies that suggest an association between short birth interval and increased adverse perinatal outcomes and wound-healing research that indicates that uterine smooth muscle tissue repair evolves over several months…. Importantly, there is radiographic and hysteroscopic evidence that cesarean scar development is incomplete as long as 6 or 12 months postoperatively.

In other words, your scar is still healing and changing 6 to 12 months after your cesarean.

To read the abstract of this study, please go here and you can obtain a free PDF of the entire study here.

Stamilio (2007) as well as the other studies that have focused on uterine rupture by interpregnancy/interbirth intervals are rather small.  It will be nice if/when larger studies are conducted so we have a better idea of the risk differential, if any, between births occurring less than 18 months post cesarean versus more than 18 months.

Does that mean that you should have a repeat cesarean if you get pregnant sooner?  I don’t think we have enough information right now to make that determination.

Also keep in mind that since you have two prior vaginal births, your likelihood of VBAC success increases to over 85% (Landon, 2005).

You can read more by looking through my bibliography.  Search for the terms ‘interbirth’ (time between cesarean birth and subsequent birth) and ‘interpregnacy’ (time between beginning of cesarean pregnancy and the beginning of subsequent pregnancies.)

Best of luck with your decision!

Warmly,

Jen

Stamilio, D. M., DeFranco, E., Pare, E., Odibo, A. O., Peipert, J. F., Allsworth, J. E., et al. (2007). Short Interpregnancy Interval: Risk of Uterine Rupture and Complications of Vaginal Birth After Cesarean Delivery. Obstetrics & Gynecology , 110 (5), 1075-1082.

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Lightning - Tucson, AZ

Lightning strikes, shark bites & uterine rupture

Lightning - Tucson, AZWhen 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

brothers-baby-siblings

AAFP National VBAC Guidelines

Update: In May 2014, the AAFP released new guidelines.

This is a great piece for deciding between VBAC and repeat cesarean.  Those who wish to VBAC, but have husbands, family, and/or friends who don’t understand why, might find this document very useful.

I have found that people who are anti-VBAC really seem impressed by what doctors and medical organizations have to say, so I’m thinking they will find this document compelling.

Plus, VBAC has this reputation of being “risky” and repeat cesareans are thought of as the “conservative approach,” and this document challenges both lines of thinking.

Why not write a sweet little note like, “I know you are concerned about me choosing the VBAC, so I thought you would find this interesting,” and mail them a copy.  That way, they can read it, think it over, and you can chat about it later.

No one wants to see a loved one hurt or die, and since most believe that a repeat cesarean is the most conservative approach, they tend to lean in that direction.  However, once they understand that real, but small, risks are present with VBAC and repeat cesarean, and that the risks of VBAC go down with each VBAC whereas the risks of cesareans go up with each surgery, hopefully they will respect your decision.

I recommend bringing this document with you when you go to interview OBs about VBAC.  They might be unfamiliar with the data, and they too might be persuaded by a document written by a medical organization.  If your OB is anti-VBAC, this might be a good document to mail them once you have found a truly supportive OB or midwife.

I’ve included the entire text below because when I searched on Google for VBAC vs. Repeat Cesarean, it wasn’t on the first page of results, so I’d like to bring more attention to it.

Please note, they refer to VBAC as TOLAC (Trial of Labor After Cesarean.)

You can view and print the document in PDF format here: Trial of Labor After Cesarean: A Shared Patient-Physician Decision Tool.

******************************************************************

In March 2005, the American Academy of
Family Physicians published an evidence based
clinical practice guideline on TOLAC
(Trial of Labor After Cesarean; formerly called
Trial of Labor Versus Elective Repeat Cesarean
Section for the Woman With a Previous
Cesarean Section).
The AAFP guideline
recommends offering a trial of labor to women
who have had one previous cesarean delivery
with a low transverse incision. The guideline
also recommends that physicians and other
maternity care professionals explore the risks
and benefits associated with a trial of labor with
each woman who is a candidate for TOLAC.
The following shared patient-physician decision
tool can be used to initiate the conversation
about the potential risks and benefits of TOLAC.
It is important to note that this piece is not
a patient education handout. It is not meant
to be used as a standalone tool. Physicians
should go through each section with the
TOLAC candidate and explain how each factor
may (or may not) affect her. After answering
any questions the patient may have, the
physician can give the annotated handout to
the patient so she and her partner can review
it as they consider their options.
To read the AAFP’s TOLAC Guideline, visit
http://www.aafp.org/tolac.

Patient name: ____________________________________________________
Physician: _______________________________________________________
________________________________________________________________
________________________________________________________________

Trial of Labor After Cesarean:
Deciding What’s Right for You
and Your Baby

Women who have had a baby by cesarean section (C-section)
may have a choice about how to have their next
baby. They may choose to have another C-section. This
is called an “elective repeat cesarean delivery” (ERCD for
short). Or they may decide to try having the baby vaginally.
This is called a “trial of labor after cesarean” (TOLAC). When
a woman tries a trial of labor and is able to deliver vaginally,
this is called a “vaginal birth after cesarean” (VBAC).

If you’re reading this handout, it’s because your doctor
has decided that you have a choice between a planned
C-section and a trial of labor. To help you understand the
risks and benefits of each, you doctor will go through
this handout with you. He or she will explain how the
factors below apply to you. Be sure to ask your doctor any
questions you have. It’s important that you understand all
of the issues before you make a decision.

If I try labor, how likely am I to have my baby vaginally?
Because every situation is different, no one can tell if you
will be able to give birth vaginally. However, you should
know that about 76 out of 100 women who try a trial of
labor deliver their babies vaginally.

What happens to women who try labor but can’t
deliver vaginally?
Some women who try a trial of labor are not able to deliver
vaginally and end up having an unplanned C-section. You
should know that most of the babies born by unplanned
C-section are healthy and do not have long-term problems
from the C-section.

Is it is safer trying labor or having a planned C-section?
You already know that having a baby—whether vaginally or
by C-section—has some risks. The risks are generally small
whether you choose a trial of labor or planned C-section.
Studies have shown that there is no difference between
the two when it comes to the woman’s risk of death or
hysterectomy. There are, however, a few other risks to
consider. These are explained below.

Infection. Of women who choose a trial of labor,
7 out of 100 will get an infection. By comparison,
9 or 10 out of 100 women who choose planned
C-section will get an infection. This means that women
who choose C-section have a slightly higher risk of
infection (2% to 3% higher) than women who choose a trial
of labor.

Uterine rupture. A C-section leaves a scar on the
uterus. During a trial of labor, the scar can break open.
Usually this doesn’t affect you or the baby. In rare cases,
however, it can pose serious risks to you or your baby.
This is called symptomatic uterine rupture and it occurs
in 2.7 out of 1,000 women, or about ¼ of 1%, who try a
trial of labor.

Infant death. Sometimes—but not always—uterine rupture
results in the death of the baby. The chance of
this is about 15 in 100,000, or about 1/100th of 1%, in
women who try a trial of labor. There is no good data
about the risk of infant death for women who choose
elective repeat C-section.

What factors affect my chances of delivering
vaginally?
Doctors have studied thousands of women who have
attempted a trial of labor. They found that the following
factors affect a woman’s chance of delivering vaginally.
Your doctor will tell you how these factors apply to you.
You might want to ask your doctor to put a checkmark
next to the factors that may affect you and to cross out
the ones that probably won’t.

Factors that increase the likelihood of a
vaginal birth after C-section (VBAC)

• Being younger than 40 years old. If you’re under 40,
you are 2½ times more likely to have a VBAC.
My age: _________
Other notes: ________________________________
__________________________________________
__________________________________________
__________________________________________

• Having a vaginal birth before. If you’ve ever had a
baby vaginally, you’re more likely to be able to deliver
that way again.
I had a baby vaginally, but it was before I had a
C-section. You are 1½ to 2 times more likely to
deliver vaginally again.
I had a baby vaginally after I had a baby by
C-section. You are 3 to 8 times more likely to
have a VBAC.
Notes about your previous delivery or deliveries:
__________________________________________
__________________________________________
__________________________________________
Other notes: ________________________________
__________________________________________
__________________________________________
__________________________________________

• Having favorable cervical factors during labor. This
means that your cervix is dilated (open) and effaced
(thinned out) enough to deliver vaginally. If you’re well
dilated and effaced, you are 1½ to 5 times more likely
to have a VBAC. If you’ve had a vaginal birth before,
your cervix may open and thin out more quickly than if
you haven’t. If you haven’t had a vaginal birth, it’s hard
to tell how well dilated and effaced your cervix will
become during labor.
I have had a previous vaginal birth.
Other notes: ________________________________
__________________________________________
__________________________________________

• If the reason you needed a C-section before isn’t
a factor this time. You might have needed a
C-section because of infection, difficult labor, breech
presentation, or concerns about the baby’s size or
heart rate. If you don’t have the same problem this
time, you are 2 times more likely to have a VBAC.
Reason for my previous C-section: ______________
__________________________________________
__________________________________________
__________________________________________
Other notes: ________________________________
__________________________________________
__________________________________________
__________________________________________
Factors that decrease the likelihood
of a VBAC

• Having had more than one C-section. If you have had
two or more C-sections, you’re 60% less likely to have
a VBAC.
Number of C-sections I’ve had: _________
Other notes: ________________________________
__________________________________________
__________________________________________
__________________________________________

 

• Going into labor after 40 weeks. After this time, you
are 20% to 30% less likely to have a VBAC.
My baby’s current gestational age: ________
My previous child(ren)’s gestational age(s) at birth:
__________________________________________
__________________________________________
__________________________________________
Other notes: ________________________________
__________________________________________
__________________________________________
__________________________________________

RISK OF SYMPTOMATIC UTERINE
RUPTURE IN ALL WOMEN
For all women . . . . . . . . . . . . . . Less than 1 birth per 1,000
For women who have
not had a C-section . . . . . . . . . Less than 1 birth per 1,000
For women who have an
elective repeat C-section . . . . About 1 birth per 1,000
For women who have a trial
of labor after C-section . . . . . . 2 to 4 births per 1,000
(800) 274-2237 • www.aafp.org

• Trying to deliver a baby that is 8 pounds, 13 ounces
(4,000 grams) or larger. If your baby weighs this much
(or more), you are 40% less likely to have a VBAC.
My baby’s current estimated weight: ____________
My previous child(ren)’s weight(s) at birth: _______
Other notes: ________________________________
__________________________________________

• Using medicines to induce or augment labor. If you
need medicine to start or help your labor, you are 50%
less likely to have a VBAC.
Notes: _____________________________________
__________________________________________

What if I have other concerns?
In addition to thinking about your health and that of your
baby, you’re probably dealing with emotional issues
and practical concerns about the birth. Some common
concerns are listed below. When you read through this
list, you may want to put a checkmark next to the issues
you really care about and cross out those that aren’t
as important to you. Talk with your doctor about your
concerns. These issues haven’t been studied like the ones
above, but your doctor may be able to give you some
insight into how they might affect you.

Recovery time. If you deliver vaginally, you’ll probably
spend less time in the hospital and be back on your
feet more quickly. Some women think this is important
because they’ll be caring for the new baby and their older
children too.

Involvement in the delivery. For some women, having a
baby vaginally is more emotionally satisfying than having
a C-section. You get to hold your baby sooner, which
may help with bonding and even with breastfeeding. Your
partner may feel more involved in a vaginal birth too.

Future childbearing. Doctors typically don’t want women
to have more than two or three C-sections. So, you’re more
likely to be able to have more children if you have a vaginal
birth instead of another C-section.

Planned versus unplanned delivery date. Because
it’s better to go into labor on your own when you’re
planning a trial of labor, you probably won’t be able to
be induced. Not knowing when you will go into labor can
be stressful. It can also be a problem if you can’t arrange
for someone to watch your other child or children at a
moment’s notice. For these reasons, some women prefer
to plan on a C-section.

Pain during labor and delivery. If you had an especially
difficult and painful labor before, you may fear going
through it again. For this reason, some women prefer to
have another C-section and avoid labor. It’s important to
remember, though, that there are ways to manage the pain
if you decide on a trial of labor.

How do I make this choice?
You and your partner should work with your doctor to
decide whether the benefits of a trial of labor outweigh
the risks.

If you decide to try labor, you and your doctor will talk
about what to do if it looks like your labor is running into
complications. It’s best to have a plan before you begin your
labor so that you don’t have to make decisions during labor.
References

1. Wall E, Roberts R, Deutchman M, Hueston W, Atwood LA, Ireland B.
Trial of labor after cesarean (TOLAC), formerly trial of labor versus
elective repeat cesarean section for the woman with a previous
cesarean section. Leawood, Kan.: American Academy of Family
Physicians; March 2005.
2. Guise J-M, McDonagh M, Hashima J, Kraemer DF, Eden KB,
Berlin M, et al. Vaginal Birth After Cesarean (VBAC). Evidence
Report/Technology Assessment No. 71. Rockville, Md.: Agency for
Healthcare Research and Quality; March 2003. AHRQ Publication
No. 03-E018.
3. Gardeil F, Daly S, Turner MJ. Uterine rupture in pregnancy reviewed.
Eur J Obstet Gynecol Reprod Biol 1994;56:107-10.
4. Miller DA, Goodwin TM, Gherman RB, Paul RH. Intrapartum rupture
of the unscarred uterus. Obstet Gynecol 1997;89:671-3.
5. Kieser KE, Baskett TF. A 10-year population based study of uterine
rupture. Obstet Gynecol 2002;100:749-53.

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elevator down

Uterine rupture risk drops significantly after first VBAC

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

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

Read the abstract below, link to the study abstract, or read the full text.

This is one of many studies that the journal Obstetrics & Gynecology provides to the public, full-text, for free without registration.


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

ABSTRACT

OBJECTIVE: To estimate the success rates and risks of an attemptedvaginal birth after cesarean delivery (VBAC) according to thenumber of prior successful VBACs.

METHODS: From a prospective multicenter registry collectedat 19 clinical centers from 1999 to 2002, we selected womenwith one or more prior low transverse cesarean deliveries whoattempted a VBAC in the current pregnancy. Outcomes were comparedaccording to the number of prior VBAC attempts subsequent tothe last cesarean delivery.

RESULTS: Among 13,532 women meeting eligibility criteria, VBACsuccess increased with increasing number of prior VBACs: 63.3%,87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and4 or more prior VBACs, respectively (P uterine rupture decreased after the first successful VBAC anddid not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52%(P=.03). The risk of uterine dehiscence and other peripartumcomplications also declined statistically after the first successfulVBAC. No increase in neonatal morbidities was seen with increasingVBAC number thereafter.

CONCLUSION: Women with prior successful VBAC attempts are atlow risk for maternal and neonatal complications during subsequentVBAC attempts. An increasing number of prior VBACs is associatedwith a greater probability of VBAC success, as well as a lowerrisk of uterine rupture and perinatal complications in the currentpregnancy.

LEVEL OF EVIDENCE: II

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