Uddin and colleagues (2013) reported the proportion of women with a prior cesarean delivery who underwent TOLAC. This number peaked in 1995, when slightly more than half of all of these women chose this option. Since that time,
FIGURE 31-2 Percentage of births with trial of labor among all deliveries with a prior cesarean delivery and percentage ofsuccessful trials oflabor among all trials oflabor ater caesarean delivery in the United States, 1990-2009. TOLAC = trial of labor ater cesarean delivery; VBAC = vaginal birth after cesarean delivery. (Data from Uddin SFG, Simon AE: Rates and success rates oftrial of labor ater cesarean delivery in the United States, 1990-2009. Matern Child Health J 17:1309,2013.) the Oice of Medical Applications of Research (0MAR) convened an NIH Consensus Development Conference Panel (2010) to study the issues of VBAC. The panel report included a contemporaneous summary concerning the risks and benefits of repeat cesarean versus vaginal delivery. These indings are subsequently described along with summaries of current recommendations by various professional organizations. Importantly, data from California indicate that VBAC rates have not perceptibly increased since the 2010 NIH Consensus Conference (Barger, 2013).
For the woman who has had a previous cesarean delivery, planning for future pregnancies and the delivery route should begin with preconceptional counseling and be addressed once again early in prenatal care. Importantly, any decision is subject to continuing revisions as dictated by exigencies that arise during pregnancy. Assuming no mitigating circumstances, there are two basic choices. First, a TOAC ofers the goal of achieving VBA. If cesarean delivery becomes necessary during the trial, then it is termed a "failed trial oflabor." A second choice is elective repeat cesarean delivey (ERCD). his includes scheduled cesareandelivery as well as unscheduled but planned cesarean delivery for spontaneous labor or another indication.
he ultimate decision should weigh clinical factors known to influence TOLAC success as well as benefits and risks. As expected, these rates vary between institutions and providers. Factors that inluence a successful TOLAC are listed in Table
Finally, economic, staing, and medicolegal factors may shape the decision to ofer TOLAC.
the proportion of women attempting TOLAC declined to a nadir in 2006 of about 16 percent and has subsequently increased to 20 to 25 percent through 2009. These investigators further reported that the percentage of VBACs reached its peak in 2000 with approximately 70 percent ofwomen being successful, but this has subsequently declined to a nadir of 38 percent in 2008 (Fig. 31-2).
In reality, several other interrelated factors-both medical and nonmedicalhave undoubtedly contributed to declining VBAC rates. Because of their complexity and importance, the Eunice Kennedy Shriver National Institute of Child Health and Human Devel
TABLE 31-1. Some Factors That Influence a Successful Trial of Labor in a Woman with Prior Cesarean Delivery aMost consider these absolute contraindications. EGA = estimated gestational age.
As evidence mounted that the risk of uterine rupture might be greater than expected, the American College of Obstetricians and Gynecologists (1988, 1998, 1999, 2017a) issued updated Practice Bulletins supporting labor trials but also urging a more cautious approach. It is problematic that both options have risks and beneits to mother and fetus but that these are not always congruent.