Category Archives: Evidence based medicine

myth versus reality

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

myth versus reality

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

rutpures in scarred uteri

Two-Thirds of OB-GYN Guidelines Have No Basis in Science

PushNews from The Big Push for Midwives Campaign
CONTACT: Katherine Prown, (414) 550-8025, katie@pushformidwives.org
FOR IMMEDIATE RELEASE: August 15, 2011
Study: Two-Thirds of OB-GYN Clinical Guidelines Have No Basis in Science
Majority of ACOG Recommendations for Patient Care Found to Be Based on Opinion and Inconsistent Evidence
WASHINGTON, D.C. (August 15, 2011)—A study published this month in Obstetrics & Gynecology, the journal of the American College of Obstetricians and Gynecologists, found that barely one-third of the organization’s clinical guidelines for OB/GYN practice meet the Level A standard of “good and consistent scientific evidence.” The authors of the study found instead that the majority of ACOG recommendations for patient care rank at Levels B and C, based on research that relies on “limited or inconsistent evidence” and on “expert opinion,” both of which are known to be inadequate predictors of safety or efficacy.

“The fact that so few of the guidelines that govern routine OB/GYN care in this country are supported by solid scientific evidence—and worse, are far more likely to be based on anecdote and opinion—is a sobering reminder that our maternity care system is in urgent need of reform,” said Katherine Prown, PhD, Campaign Manager of The Big Push for Midwives. “As the authors of the study remind us, guidelines are only as good as the evidence that supports them.”

ACOG Practice Bulletin No. 22 on the management of fetal macrosomia—infants weighing roughly 8 ½ lbs or more at birth—illustrates the possible risks to mothers and babies of relying on unscientific clinical guidelines. The only Level A evidence-based recommendation on the delivery of large-sized babies the Bulletin makes is to caution providers that the methods for detection are imprecise and unreliable. Yet at the same time, the Bulletin makes a Level C opinion-based recommendation that, despite the lack of a reliable diagnosis, women with “suspected” large babies should be offered potentially unnecessary cesarean sections as a precaution, putting mothers at risk of surgical complications and babies at risk of being born too early.

“It’s no wonder that the cesarean rate is going through the roof and women are seeking alternatives to hospital-based OB/GYN care in unprecedented numbers,” said Susan M. Jenkins, Legal Counsel of The Big Push for Midwives. “ACOG’s very own recommendations give its members permission to follow opinion-based practice guidelines that have far more to do with avoiding litigation than with adhering to scientific, evidence-based principles about what’s best for mothers and babies.”

The Big Push for Midwives Campaign represents tens of thousands of grassroots advocates in the United States who support expanding access to Certified Professional Midwives and out-of-hospital maternity care. The mission of The Big Push for Midwives is to educate state and national policymakers and the general public about the reduced costs and improved outcomes associated with out-of-hospital maternity care and to advocate for expanding access to the services of Certified Professional Midwives, who are specially trained to provide it.

Media inquiries: Katherine Prown (414) 550-8025, katie@pushformidwives.org

ACOG-logo

ACOG issues less restrictive VBAC guidelines

Wow, Practice Bulletin No. 115, replacing No. 45 is a breath of fresh air.  No. 45 included the infamous “immediately available” phrase resulting in a fire of VBAC bans to rage around the country, but primarily in rural areas.  Surely No. 115 is in response to the NIH’s March 2010 VBAC conference and the VBAC Statement it produced.

In short, VBAC is a “safe and appropriate choice for most women” with one prior cesarean and for “some women” with two prior cesareans.  Being pregnant with twins, going over 40 weeks, having an unknown or low vertical scar, or suspecting a “big baby” should not prevent a woman from planning a VBAC (ACOG, 2010).

What follows is a brief overview of these new guidelines.

They express support for VBAC after one and two prior cesareans:

Attempting a VBAC is a safe and appropriate choice for most women who have had a prior cesarean delivery including for some women who have had two previous cesareans.

They express support for VBAC with twins or unknown scars:

The College guidelines now clearly say that women with two previous low-transverse cesarean incisions, women carrying twins, and women with an unknown type of uterine scar are considered appropriate candidates for a TOLAC.

They say a Pitocin induction remains an option:

Induction of labor for maternal or fetal indications remains an option in women undergoing TOLAC [trial of labor after cesarean…Misoprostol [Cytotec] should not be used for third trimester cervical ripening or labor induction in patients who have had a cesarean delivery or major uterine surgery.

They detail the risks that can come with multiple cesareans which are often not listed in your standard “informed consent” document:

[VBAC] may also help women avoid the possible future risks of having multiple cesareans such as hysterectomy, bowel and bladder injury, transfusion, infection, and abnormal placenta conditions (placenta previa and placenta accreta).

But what will have the most impact on the most women is the lifting of the “immediately available” recommendation turned requirement as suggested by the NIH VBAC Conference:

The [American] College [of Obstetricians and Gynecologists] maintains that a TOLAC is most safely undertaken where staff can immediately provide an emergency cesarean, but recognizes that such resources may not be universally available.

They acknowledged how the phrase “immediately available” in their last recommendation were used to support VBAC bans:

“Given the onerous medical liability climate for ob-gyns, interpretation of The College’s earlier guidelines led many hospitals to refuse allowing VBACs altogether,” said Dr. Waldman. “Our primary goal is to promote the safest environment for labor and delivery, not to restrict women’s access to VBAC.”

And they now support hospitals who do not meet the “immediately available” standard attending VBACs:

Women and their physicians may still make a plan for a TOLAC in situations where there may not be “immediately available” staff to handle emergencies, but it requires a thorough discussion of the local health care system, the available resources, and the potential for incremental risk.

Finally, they assert how women should not be force to have a repeat cesarean against their will and that women should be referred out to VBAC supportive practitioners if their current care provider would rather not attend a VBAC:

The College says that restrictive VBAC policies should not be used to force women to undergo a repeat cesarean delivery against their will if, for example, a woman in labor presents for care and declines a repeat cesarean delivery at a center that does not support TOLAC. On the other hand, if, during prenatal care, a physician is uncomfortable with a patient’s desire to undergo VBAC, it is appropriate to refer her to another physician or center.

Removing the “immediately available” standard while supporting VBAC with twins, after two prior cesareans, and with unknown scars is a huge step in the right direction.  It seems that the option of VBAC is now available to hundreds of thousands of women, many of whom, up to this point, were left with no choice at all.

Read the whole press release dated July 21, 2010: Ob-Gyns Issue Less Restrictive VBAC Guidelines.

Download the PDF: Practice Bulletin #115, “Vaginal Birth after Previous Cesarean Delivery,” is published in the August 2010 issue of Obstetrics & Gynecology.

The College maintains that a TOLAC is most safely undertaken where staff can immediately provide an emergency cesarean, but recognizes that such resources may not be universally available. “Given the onerous medical liability climate for ob-gyns, interpretation of The College’s earlier guidelines led many hospitals to refuse allowing VBACs altogether,” said Dr. Waldman. “Our primary goal is to promote the safest environment for labor and delivery, not to restrict women’s access to VBAC.” Women and their physicians may still make a plan for a TOLAC in situations where there may not be “immediately available” staff to handle emergencies, but it requires a thorough discussion of the local health care system, the available resources, and the potential for incremental risk. “It is absolutely critical that a woman and her physician discuss VBAC early in the prenatal care period so that logistical plans can be made well in advance,” said Dr. Grobman. And those hospitals that lack “immediately available” staff should develop a clear process for gathering them quickly and all hospitals should have a plan in place for managing emergency uterine ruptures, however rarely they may occur, Dr. Grobman added. The College says that restrictive VBAC policies should not be used to force women to undergo a repeat cesarean delivery against their will if, for example, a woman in labor presents for care and declines a repeat cesarean delivery at a center that does not support TOLAC. On the other hand, if, during prenatal care, a physician is uncomfortable with a patient’s desire to undergo VBAC, it is appropriate to refer her to another physician or center.

Interview with Dr. Fischbein: An Inside Look at Hospitals and VBAC Bans

Stand and Deliver recently conducted an excellent interview with Dr. Stuart Fischbein, a Southern California VBAC and breech supportive OB.  It’s an excellent read and I’m including my favorite parts below.  You can read the entire article here: Stand and Deliver: Interview with Dr. Stuart J. Fischbein.

First, let’s do  quick review of ACOG’s Practice Bulletin #54, published in July 2004 and the reason why some American hospitals have banned VBAC, recommends, “a physician [be] immediately available throughout active [VBAC] labor who is capable of monitoring labor and performing an emergency cesarean delivery.”

Now that we are all on the same page, here are excerpts from Dr. Fischebin’s interview:

Don’t hospitals ban VBAC because it is dangerous?

They ban VBACs under the guise of patient safety. But patient safety is a euphemism for “we don’t have a good evidence-based reason to do it, other than we don’t want to get sued, it’s more expedient, and we make more money from c-sections—the hospital does, not necessarily the physician, but the hospital does—so we’re going to ban it because it’s easier for us, and we’re going to say it’s for patient safety because of the risk of rupturing the uterus.” But you know what? That risk should be something that the patient decides. Patients have a right to be given informed consent, free from misinformation or coercion, free from skewing information that benefits the practitioner or the hospital. And they have the right to consent or refuse to accept the treatment that’s offered. That right is frequently being denied.

What role does malpractice insurance play in VBAC availability?

The reason that a lot of hospitals ban VBACs anyway [despite meeting ACOG’s “immediately available” recommendation] —and this isn’t very well known to most people—is because their insurance carrier will tell them that if they allow VBACs, their premium will be much higher. Rather than pay higher premiums, they just ban VBACs and do so under the guise of patient safety. The hospital lawyers, the insurance company lawyers, the insurance company executives, and the hospital administrators are making decisions for patients and then lying about why they’re doing it.

Aren’t uterine ruptures the primary reason for repeat cesareans in women with a prior cesarean?

Most emergency c-sections, the ones that occur suddenly, have nothing to do with a uterine rupture.  They are for placental abruption, prolapsed cord, or prolonged fetal heart rate decelerations.  Far more often, it’s something unrelated to the VBAC that causes an emergency.  And somehow the hospital can manage to take care of those situations. If hospitals can take care of those things, why can they not take care of VBACs?

ACOG’s latest VBAC recommendation was based on consensus opinion, not scientific evidence.  Doesn’t that matter to hospitals when implementing VBAC bans?

Ultimately it won’t matter to the hospital. It’s not about evidence-based medicine. It’s very clear to me in discussing this with the committees that they don’t care. They’re being told by the risk managers, the lawyers, and the insurance companies that they cannot do VBACs. And that’s the final word. The anesthesia departments are also often behind VBAC bans. They talk about patient safety, but really it is that reimbursement is so bad and they don’t want to have to sit around in the hospital all day long and they are fearful of being sued.

Do hospital administrators impact how an OB counsels a woman on VBAC?

I’m supposed to tell patients that they have to go elsewhere if they want a VBAC, that they can’t stay in their own community, that they have to drive 50 miles. … I’m not supposed to tell them that they have the option of showing up in labor and refusing surgery. The hospital actually put in writing that I should avoid telling them that. They’re telling me to skew my counseling, and they have no shame in doing so.

How do OBs feel about working in hospitals with VBAC/breech bans?

For physicians who are not really committed to doing VBACs or breeches, it’s a lot easier to do a section. You get paid about the same. With a section, you can do the surgery at 7:30 am and you’re in the office by 9 am. If you have a breech or a VBAC, you have to cancel your day or spend the night at the hospital. It’s a lot more work, and you don’t get paid any more for it. So you really have to be either dedicated or crazy or somewhere in between. You have to keep your ethical feet well-grounded.

How do VBAC bans impact hospital revenues?

For hospitals, it’s easy. Does a hospital make more money off a practice that has a 5% c-section rate or a 25% c-section rate? That’s an easy question. Although they will never admit that; [the official reason for VBAC bans] will always be patient safety. Clearly, there’s no incentive for them to offer a VBAC to anybody.

How do VBAC bans impact women seeking VBAC?

A successful VBAC occurs about 73% of the time. If a hospital bans VBAC, they’re basically telling 73% of women that they have to undergo a surgical procedure that carries more morbidity than if they had a vaginal birth.

How could tort reform impact VBAC supportive OBs and birthing women?

[With] tort reform, you might be able to make changes by improving competition. If you get rid of some of the restrictions on businesses, you might see more competition start up. You might see more birth centers open, or birth centers that actually have operating rooms, little maternity hospitals. Just like we’ve seen specialty surgery centers open up recently. For years hospitals tried to squelch these things because they know they can’t compete with them. Some day, maybe the major hospital model will go out of business. And would that be so terrible? We have specialty hospitals that do heart surgeries, gastric bypass, or plastic surgery. Why not specialty hospitals that just do maternity? Run by doctors and midwives.