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Editorial MAY 2010

Don’t Throw Out the Baby With the Bathwater: Time to Revisit VBAC

Ronald T. Burkman, MD

This month’s The Female Patient provides a review of the current status of vaginal birth after cesarean (VBAC), including an approach to estimate the likelihood of success. The article affords us an opportunity to examine the consequences of continuing to abandon VBAC and reinstituting routine repeat cesarean delivery.

First, it is important to emphasize that if a scheduled repeat cesarean delivery is planned, it should be carried out at 39 to 40 weeks’ gestation. A recent prospective cohort study of more than 24,000 cesarean deliveries demonstrated that the risk for neonatal morbidity associated with this surgery was lowest at 39 to 40 weeks, compared with earlier than 39 or later than 40 weeks of gestation. Cesarean deliveries carried out at this time also have a reasonably low risk for urgent surgery due to labor-related problems.

However, it is also instructive to examine the risks faced by women who undergo repeat cesarean deliveries. The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network, using a cohort of more than 30,000 women who had undergone cesarean delivery without labor, evaluated the maternal morbidity associated with repeat cesarean deliveries. They noted that with each subsequent cesarean delivery, the risk increased for placenta accreta, hysterectomy, urologic injury to the bladder and ureter, bowel injury, multiple blood transfusions, and a longer hospital stay. For example, by the third cesarean delivery, the risk of placenta accreta had doubled compared with women undergoing an initial cesarean delivery. Among women undergoing a fifth or sixth cesarean delivery, this complication was present in 2.3% and 6.7% of cases, respectively.

Since placenta accreta is frequently associated with placenta previa, the researchers also examined the risk for this complication among women who had this type of placentation. Although only 11% of women with placenta previa undergoing a second cesarean delivery also had an accreta, by the fourth cesarean delivery almost two-thirds of these women had an accreta. In reviewing the women requiring hysterectomy, by the third cesarean birth almost 1% required a hysterectomy to manage a complication; by the fourth, the rate had climbed to 2.4%, and for women undergoing 6 or more cesarean deliveries, the number of patients requiring hysterectomy had risen to 9%.

So what does this mean relative to our practice? Women who have undergone a primary cesarean delivery and desire several children need to be informed of the risks associated with multiple repeat cesarean deliveries. Further, to avoid serious morbidity, VBAC should be considered for many of these women. Unfortunately, one of the barriers has been the ACOG practice bulletin on VBAC published in 2004 that stated VBAC should be attempted only in facilities where physicians are “immediately available” to provide emergency care and where there are adequate personnel to carry out surgery. This recommendation was made even though the risk of uterine rupture during VBAC after one prior cesarean delivery with a transverse incision is less than 1% for most women. The concern was that some of these ruptures may be catastrophic. Yet, there is no special staffing required for the possibility of a placental abruption, which also can be catastrophic.

It is important to note that this recommendation was based on opinion and, like all ACOG practice bulletins, should not be considered to represent the “standard of care” or the only way to practice. Unfortunately, it led most smaller hospitals, in particular, to abandon all VBACs, due to the inability to always provide the ACOG-recommended staffing and concern regarding the potential for litigation, should an untoward event occur. Yet many women are at very low risk for significant morbidity, as noted by Costantine and Grobman in this issue. For example, using the model described in their article, a 25-year-old with a BMI of 30 who has never delivered vaginally and whose first cesarean delivery was not related to failure to descend or dilate has about a 73% probability of a successful VBAC. They also note the risk of a major complication such as hysterectomy is similar for women with a probability of successful VBAC of at least 70% and for those undergoing a repeat cesarean delivery.

Given this type of information, hospitals should reevaluate their policies regarding VBAC. For example, most hospitals could modify their policy to allow VBAC in very-low-risk situations, using the same staffing model as their backup for all women laboring at the facility. Such an approach has been used in most of the hospitals in Vermont and New Hampshire for a number of years. VBAC candidates are classified by risk, and then staffing and other measures are adjusted depending on their classification. Finally, a recent NIH Consensus Development Conference, “Vaginal Birth After Cesarean: New Insights,” supported the concept of risk stratification and the avoidance of unnecessary barriers such as rigid staffing levels for all women undergoing VBAC, regardless of their risk status.

To me, the current situation is similar to that which occurred in the early 1980s with intrauterine devices (IUDs). Due to litigation regarding infection with the devices, particularly the Dalkon Shield, most US practitioners stopped using these devices altogether, even though the vast majority of the litigation was not directed against them. In other countries, however, the selection criteria for IUD candidates were altered to exclude women with or at risk for sexually transmitted infections. This led to a dramatic fall in the rates of infection, and the use of IUDs continued to be a significant part of the contraceptive armamentarium in those countries.

Our fear of litigation is also fueling our reluctance to use VBAC, even though there are many women who can safely labor after a prior cesarean delivery. Let’s do what is right for these women and not throw out the baby with the bathwater again!

Ronald T. Burkman, MD, Editor-in-Chief