Vaginal Birth After Cesarean (VBAC) - Is it Safe?

Study Finds Induction Increases Risks for VBACs

Mona Lydon-Rochelle, Holt, Victoria L., Easterling, Thomas R., Martin, Diane P. "Risk of Uterine Rupture during Labor among Women with a Prior Cesarean Delivery" New England Journal of Medicine, Vl 345, No. 1, July 5, 2001.

A new study that looks at the risk of uterine rupture during labor for VBACs (vaginal birth after cesarean-section) was picked up by newspapers across the country, but many headlines announced that VBACs are dangerous, a gross distortion of the study's findings. National organizations including the ACNM and the International Cesarean Awareness Network issued press releases, and through the Grassroots Network CfM urged people to respond with letters to the editor of their local newspapers.

The most important finding was that for hospital VBACs (after one c-section) induction of labor significantly increases the risk of uterine rupture, and the use of protoglandins greatly increases the risk of rupture (15 times higher than those who had second cesaraeans). In other words, the real problem is the first c-section (which accounts for 2/3 of the US c-section rate of 22% in 1999), with the risks greatly increased when labor is induced especially with prostaglandins.

Data for women who had a first (single) baby by c-section from 1987-1996, and subsequently gave birth to a second live single infant during the same period of time (20,095 women, based on Washington State records for hospital births), were analyzed in this study. The study found:

Repeat c-section without labor 1.6 (11 of 6,980 women)
Spontaneous onset of labor 5.2 (56 of 10,789 women)
Labor induced without prostaglandins 7.7 (15 of 1,960 women)
Labor induced with prostaglandins 24.5 (9 of 366 women)

The study did not address many significant issues. For example, uterine rupture can include anything from relatively minor separations at the scar site, to sudden and catastrophic multiple large tears of the uterus. However, accuracy of reported uterine rupture was barely touched upon, and degrees of severity were not discussed. Because the study focused only on the risk of uterine rupture, the risks associated with the cesarean delivery procedure itself were not discussed, even though these would be very relevant for informed decision-making. There was no mention of other interventions that could possibly affect outcomes, such as augmentation of labor (can cause abnormally strong contractions) or the use of epidurals during labor (can mask early symptoms of uterine rupture). The authors did acknowledge that they lacked information regarding specific types and dosages of prostaglandins used, although the controversial use of Cytotec was not known to be used prior to the last year of the study. Finally, there was no discussion or information regarding the timing (number of weeks of gestation) or reasons for induction.

The study included only hospital births, and did not distinguish between natural childbirth (no interventions) and standard hospital-managed birth.

The study actually confirms what the midwifery community has been saying for years: outcomes for VBACs that are allowed to labor normally, without induction or augmentation, are good. And women who have had a previous c-section are definitely not candidates for labor inducing drugs, which exert added stress to a uterine wall that is already weakened or at least changed by the scar tissue.

Women who are making decisions about attempting a VBAC should understand the results of this study (and its limitations). In addition, this information is essential for any woman who is "offered" an elective c-section, or whose caregiver recommends a c-section, so she can be aware that a c-section today significantly increases risks associated with any future pregnancy. Of course, she should also have full information on the relative risks of any c-section for herself and her baby.

As ICAN states in their press release (see below), "the risk of uterine rupture [for a VBAC] remains low when labor is allowed to start on its own."



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Related Articles of Interest

  • "Trial of Labor After 40 Weeks' Gestation in Women With Prior Cesarean." Carolyn M. Zelop, Thomas D. Shipp, Amy Cohen, John T. Repke, & Ellice Lieberman Obstet Gynecol 2001;97(3):391-393. The authors concluded, "Because spontaneous labor after 40 weeks is associated with a cesarean rate similar to that following induced labor before 40 weeks, awaiting spontaneous labor after 40 weeks does not decrease the likelihood of successful vaginal delivery."
  • Press Release: "International Cesarean Awareness Network Affirms Safety of Vaginal Birth After Cesarean"

    From the ICAN Press Release:

    "In fact,the risk of rupture for women who begin labor spontaneously was shown to be 0.5%, lower than many other recent studies have shown and consistent with the body of medical literature on VBAC. Women planning VBAC should be encouraged that the risk of uterine rupture remains low when labor is allowed to start on its own."

    "In any discussion about VBAC, women must also be provided with unbiased, evidence-based information about the known risks of elective cesarean section. Babies delivered by elective cesarean section are cut during surgery 2-6% of the time, have a 9% chance of being born prematurely, and risk a 0.4% chance of developing respiratory distress syndrome, a potentially fatal complication. They spend more time in neonatal intensive care units and have more breastfeeding difficulties than babies born vaginally."

    "Cesareans also increase the risks to both mother and baby in subsequent pregnancies. Incidences of life-threatening placental abnormalities increase with each cesarean. When all short- and long-term consequences are considered, VBAC has been shown to be less risky for both mother and baby than elective repeat cesarean section."

    "Standing up to the VBAC-lash: A critique of the New England Journal of Medicine VBAC study and implications for the future of the medical model of childbirth." by Jill MacCorkle. Published on the Internet (click here). This is a thorough and well-referenced paper that also includes information regarding the risks associated with c-sections in general and the evidence supporting the benefits of VBACs.
  • For a discussion issues associated with reporting of uterine rupture, read "Use of Hospital Discharge Data to Monitor Uterine Rupture Massachusetts, 1990-1997" Morbidity and Mortality Weekly Report (March 31, 2000 / 49(12);245-8) available online (click here).



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CfM Response to NEJM VBAC Article

Dear Editor,

Birth is the leading reason for hospital admission in this country. Cesarean delivery is the most common surgery performed in the United States. The most common cause of death in postpartum women is complications from cesarean delivery.

In the face of these facts, it is shameful that the media response to the New England Journal of Medicine study (July 5, 2001) has been to focus on the risks of vaginal birth, and not the risks of routine medical interventions, such as prostaglandin induction and elective repeat cesarean.

The study points to a 0.5% risk of rupture among post-cesarean women who labor without induction. Other studies have produced similar numbers that were used to support the practice of VBAC. Why? Because even with this risk, the mother is still twice as likely to die from complications of elective repeat cesarean birth compared to vaginal birth.

Every maternity care provider has an ethical obligation to honestly describe both options to the mother as part of her informed decision-making process. Apparently there is no such obligation in the public dialogue of this issue - there is no patient, only a large and suggestible audience.

Sincerely,
Susan Hodges, President, Citizens for Midwifery
Willa Powell, Board Member, Citizens for Midwifery
Citizens for Midwifery is the only national consumer organization advocating the Midwives Model of Care

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