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

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

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

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

First, you can induce VBACs

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

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

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

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

Yet, misinformation persists

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

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

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

“vbac should never be induced!”

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

“Not supposed to induce with a VBAC.”

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

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

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

“Well, I would choose an induction…”

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

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

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

More risk than what?

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

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

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

Don’t misrepresent the facts

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

But don’t misrepresent the truth to other women.

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

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

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

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

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

Medically indicated induction = choice

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

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

Clear language provides clarity

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

Women can make informed decisions only when they are informed

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

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

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

“Induction is wrong” & patient autonomy

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

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

 

Resources Cited

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

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

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

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

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

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

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

 

What do you think? Leave a comment.

Jen Kamel

Jen Kamel is the founder of VBAC Facts, an educational, training and consulting firm. As a nationally recognized VBAC strategist and consumer advocate, she has been invited to present Grand Rounds at hospitals, served as an expert witness in a legal proceeding, and has traveled the country educating hundreds of professionals and highly motivated parents. She speaks at national conferences and has worked as a legislative consultant in various states focusing on midwifery legislation and regulations. She has testified multiple times in front of the California Medical Board and legislative committees on the importance of VBAC access and is a board member for the California Association of Midwives.

Learn more >

Free Report Reveals...

Parents pregnant after a cesarean face so much misinformation about VBAC. As a result, many who are good VBAC candidates are coerced into repeat cesareans. This free report provides quick clarity on 5 uterine rupture myths so you can tell fact from fiction and avoid the bait & switch.

VBAC Facts does not provide any medical advice and the information provided should not be so construed or used. Nothing provided by VBAC Facts is intended to replace the services of a qualified physician or midwife or to be a substitute for medical advice of a qualified physician or midwife. You should not rely on anything provided by VBAC Facts and you should consult a qualified health care professional in all matters relating to your health.

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

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

Many moms and midwives use evening primrose oil (EPO) for cervical ripening. So I was absolutely shocked at the complete lack of evidence on the effectiveness and safety of EPO use among pregnant women.

There are only two studies that examine the oral use EPO and its ability to ripen the cervix during pregnancy.  There are no studies on the vaginal use of EPO. In short, there is insufficient clinical evidence documenting the risks and benefits of EPO and without that information,  the question is, should pregnant women take it?

The available evidence on EPO

Paula Senner gives an excellent review of the first study (Dove 1999) in her Quantitative Research Proposal entitled, “Oral Evening Primrose Oil as a Cervical Ripening Agent in Low Risk Nulliparous Women” (emphasis mine),

The study group consisted of 54 women who took oral evening primrose oil in their pregnancy (500 mg three times a day starting at 37 weeks gestation for the first week of treatment, followed by 500 mg once a day until labor ensued), and the control group was composed of 54 women who did not take anything. Antepartum and intrapartum records of all women were reviewed focusing on the above identified criteria.

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

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

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

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

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

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

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

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

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

Bleeding issues could complicate cesareans

Research on the use of EPO for other aliments among non-pregnant people has suggested there could be a possible association between the use of EPO and bleeding problems during surgery.

As a result, Medline recommends that people don’t use it at least 2 weeks before a scheduled surgery.

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

We just don’t know because there is a lack of data.

Dosages and mode of delivery

Another hole in the research and our knowledge relates to dosage.

I see women reporting an incredible range of dosages on the internet. What is safe?

There are no clinical studies documenting how much women should take. Maybe X dose of EPO is good, but Y dose introduces XYZ risks.

How long should women take EPO? The last month of pregnancy? The last two weeks?  (Remember, we just read how there is a possible bleeding issue.)

Should they take it twice a day or once a day? Does the body absorb or metabolize EPO differently if it is administrated vaginally or orally?

We just don’t know the answers to these questions.

What about our bodies’ innate ability to birth?

It comes down to the fundamental question: Do our bodies need something to help us go into labor?

Many natural birth advocates reject the routine use of Pitocin augmentation during labor because they say our bodies know how to birth. Yet it’s often women from this same mindset that use EPO.

Either pregnant people as a whole need something to help them go into labor – whether that is EPO or Pitocin – or they don’t.

Are we less leery of EPO because it comes from a flower? Because it’s not produced by “big pharma?”

Because midwives suggest it more than OBs?

Because we can purchase it over the counter? Because it’s a pill, not an injection? Because we can administer it to ourselves in the comfort of our home?

Because it is used so routinely that no one questions it? Or is it simply because we all assume since everyone takes it, the evidence must be on the side of EPO?

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

When I have shared the lack of evidence on EPO’s ability to ripen cervi or prepare a woman’s body for labor, sometimes women reply with “But there is no evidence to suggest it won’t help either.”

American OBs used this same rationale when they induced scarred moms with Cytotec in the 1990s. There were no published medical studies on Cytotec induction in scarred women, so we didn’t know the risks and benefits. But people used it because we knew it caused uterine contractions. What can go wrong, right?

But the problem is, when there is a lack of clinical evidence on large populations of women, we are sometimes surprised with dire outcomes that no one could have predicted as was the case of Cytotec.

We cannot look back at that period and think, “How could they have done that” when we are now doing the same thing with EPO: using a chemical without evidence of its benefits and harms.

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

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

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

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

Anecdote vs. evidence

OBs who used Cytotec on women with a prior cesarean in the 1990s inevitably would have said, “I haven’t had a bad outcome yet,” and I suspect that many people who use EPO now would say the same thing.

When we have one woman who used EPO and had an arrest of descent, do care providers recognize that this could be as a result of the EPO?

When we have one women who used EPO and it worked as expected, how can we determine her labor progressed because of the EPO?

When you have a small sample size, it’s hard to make a connection.  It’s even more difficult to connect EPO to it’s possible list of complications when not many care providers are aware of the lack of evidence on EPO and the findings of this one lone study.

Is our limited experience, with relatively few patients, without meticulous record keeping that can detect patterns across groups of patients, sufficient evidence?  I don’t think so.

We would likely need thousands of women in order to create a sample size powerful enough to detect – or rule out – common and more rare EPO complications in addition to answering the many questions I posed above.

Take away message

I’m not saying to use EPO or not.

I’m simply pointing out how little we know about this commonly used substance and questioning if that should make a difference in how we view and/or use it.

There is limited evidence on EPO’s ability to ripen the cervix and aid with labor.  We have two studies on the oral use of EPO that looked at this question and none on the vaginal use of EPO among pregnant women.

One study found that EPO doesn’t ripen the cervix and poses considerable risk.  Another study found that EPO does ripen the cervix but those women did not go into labor sooner than the women that didn’t take EPO.

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

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

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

We need more large studies to confirm or refute the notion that EPO = ripen cervix = shorter pregnancies. Without that information, we are using a product that we know very little about.

 

Resources Cited

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

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

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

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

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

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

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

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

What do you think? Leave a comment.

Jen Kamel

Jen Kamel is the founder of VBAC Facts, an educational, training and consulting firm. As a nationally recognized VBAC strategist and consumer advocate, she has been invited to present Grand Rounds at hospitals, served as an expert witness in a legal proceeding, and has traveled the country educating hundreds of professionals and highly motivated parents. She speaks at national conferences and has worked as a legislative consultant in various states focusing on midwifery legislation and regulations. She has testified multiple times in front of the California Medical Board and legislative committees on the importance of VBAC access and is a board member for the California Association of Midwives.

Learn more >

Free Report Reveals...

Parents pregnant after a cesarean face so much misinformation about VBAC. As a result, many who are good VBAC candidates are coerced into repeat cesareans. This free report provides quick clarity on 5 uterine rupture myths so you can tell fact from fiction and avoid the bait & switch.

VBAC Facts does not provide any medical advice and the information provided should not be so construed or used. Nothing provided by VBAC Facts is intended to replace the services of a qualified physician or midwife or to be a substitute for medical advice of a qualified physician or midwife. You should not rely on anything provided by VBAC Facts and you should consult a qualified health care professional in all matters relating to your health.

Myth: 50% of uterine ruptures occur before labor

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.

Jen

Resources Cited

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

What do you think? Leave a comment.

Jen Kamel

Jen Kamel is the founder of VBAC Facts, an educational, training and consulting firm. As a nationally recognized VBAC strategist and consumer advocate, she has been invited to present Grand Rounds at hospitals, served as an expert witness in a legal proceeding, and has traveled the country educating hundreds of professionals and highly motivated parents. She speaks at national conferences and has worked as a legislative consultant in various states focusing on midwifery legislation and regulations. She has testified multiple times in front of the California Medical Board and legislative committees on the importance of VBAC access and is a board member for the California Association of Midwives.

Learn more >

Free Report Reveals...

Parents pregnant after a cesarean face so much misinformation about VBAC. As a result, many who are good VBAC candidates are coerced into repeat cesareans. This free report provides quick clarity on 5 uterine rupture myths so you can tell fact from fiction and avoid the bait & switch.

VBAC Facts does not provide any medical advice and the information provided should not be so construed or used. Nothing provided by VBAC Facts is intended to replace the services of a qualified physician or midwife or to be a substitute for medical advice of a qualified physician or midwife. You should not rely on anything provided by VBAC Facts and you should consult a qualified health care professional in all matters relating to your health.

False comparison: Fatal car accidents and VBAC

False comparison: Fatal car accidents and VBAC

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

_____________________

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.

_______________________________

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.

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.

What do you think? Leave a comment.

Jen Kamel

Jen Kamel is the founder of VBAC Facts, an educational, training and consulting firm. As a nationally recognized VBAC strategist and consumer advocate, she has been invited to present Grand Rounds at hospitals, served as an expert witness in a legal proceeding, and has traveled the country educating hundreds of professionals and highly motivated parents. She speaks at national conferences and has worked as a legislative consultant in various states focusing on midwifery legislation and regulations. She has testified multiple times in front of the California Medical Board and legislative committees on the importance of VBAC access and is a board member for the California Association of Midwives.

Learn more >

Free Report Reveals...

Parents pregnant after a cesarean face so much misinformation about VBAC. As a result, many who are good VBAC candidates are coerced into repeat cesareans. This free report provides quick clarity on 5 uterine rupture myths so you can tell fact from fiction and avoid the bait & switch.

VBAC Facts does not provide any medical advice and the information provided should not be so construed or used. Nothing provided by VBAC Facts is intended to replace the services of a qualified physician or midwife or to be a substitute for medical advice of a qualified physician or midwife. You should not rely on anything provided by VBAC Facts and you should consult a qualified health care professional in all matters relating to your health.

Can you feel a uterine rupture with an epidural?

Can you feel a uterine rupture with an epidural?

Some 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.

___

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?

What do you think? Leave a comment.

Jen Kamel

Jen Kamel is the founder of VBAC Facts, an educational, training and consulting firm. As a nationally recognized VBAC strategist and consumer advocate, she has been invited to present Grand Rounds at hospitals, served as an expert witness in a legal proceeding, and has traveled the country educating hundreds of professionals and highly motivated parents. She speaks at national conferences and has worked as a legislative consultant in various states focusing on midwifery legislation and regulations. She has testified multiple times in front of the California Medical Board and legislative committees on the importance of VBAC access and is a board member for the California Association of Midwives.

Learn more >

Free Report Reveals...

Parents pregnant after a cesarean face so much misinformation about VBAC. As a result, many who are good VBAC candidates are coerced into repeat cesareans. This free report provides quick clarity on 5 uterine rupture myths so you can tell fact from fiction and avoid the bait & switch.

VBAC Facts does not provide any medical advice and the information provided should not be so construed or used. Nothing provided by VBAC Facts is intended to replace the services of a qualified physician or midwife or to be a substitute for medical advice of a qualified physician or midwife. You should not rely on anything provided by VBAC Facts and you should consult a qualified health care professional in all matters relating to your health.

Myth: Two numbers less than 1% are similar

Myth: Two numbers less than 1% are similar

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

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

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

2% = 1 in 50 risk

89% = 1 in 1.12 risk

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

What about numbers less than 1%?

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

1 in 100 represents 1%.

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

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

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

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

Comparing small risks

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

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

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

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

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

Take away messages

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

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

Resources Cited

* Zwart (2009) differentiated between uterine rupture and dehiscence, featured 358,874 total deliveries, 25,989 of which were trials of labor after a cesarean.  Zwart included 97% of births in The Netherlands between August 1, 2004 and August 1, 2006, making it “the largest prospective report of uterine rupture in women without a previous cesarean in a Western country.”

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

What do you think? Leave a comment.

Jen Kamel

Jen Kamel is the founder of VBAC Facts, an educational, training and consulting firm. As a nationally recognized VBAC strategist and consumer advocate, she has been invited to present Grand Rounds at hospitals, served as an expert witness in a legal proceeding, and has traveled the country educating hundreds of professionals and highly motivated parents. She speaks at national conferences and has worked as a legislative consultant in various states focusing on midwifery legislation and regulations. She has testified multiple times in front of the California Medical Board and legislative committees on the importance of VBAC access and is a board member for the California Association of Midwives.

Learn more >

Free Report Reveals...

Parents pregnant after a cesarean face so much misinformation about VBAC. As a result, many who are good VBAC candidates are coerced into repeat cesareans. This free report provides quick clarity on 5 uterine rupture myths so you can tell fact from fiction and avoid the bait & switch.

VBAC Facts does not provide any medical advice and the information provided should not be so construed or used. Nothing provided by VBAC Facts is intended to replace the services of a qualified physician or midwife or to be a substitute for medical advice of a qualified physician or midwife. You should not rely on anything provided by VBAC Facts and you should consult a qualified health care professional in all matters relating to your health.