VAGINAL BIRTH AFTER CESAREAN DELIVERY
Trial of labor after cesarean delivery (TOLAC) refers to a planned attempt to deliver vaginally by a woman who has had a previous cesarean delivery, regardless of the outcome. This method provides women who desire a vaginal delivery the possibility of achieving that goal—a vaginal birth after cesarean delivery (VBAC). In addition to fulfilling a patient’s preference for vaginal delivery, at an individual level, VBAC is associated with decreased maternal morbidity and a decreased risk of complications in future pregnancies as well as a decrease in the overall cesarean delivery rate at the population level (1–3). However, although TOLAC is appropriate for many women, several factors increase the likelihood of a failed trial of labor, which in turn is associated with increased maternal and perinatal morbidity when compared with a successful trial of labor (ie, VBAC) and elective repeat cesarean delivery (4–6). Therefore, assessing the likelihood of VBAC as well as the individual risks is important when determining who is an appropriate candidate for TOLAC. Thus, the purpose of this document is to review the risks and benefits of TOLAC in various clinical situations and to provide practical guidelines for counseling and management of patients who will attempt to give birth vaginally after a previous cesarean delivery.
Background
Between 1970 and 2016, the cesarean delivery rate in the United States increased from 5% to 31.9% (7, 8). This dramatic increase was a result of several changes in the practice environment, including the introduction of electronic fetal monitoring and a decrease in operative vaginal deliveries and attempts at vaginal breech deliveries (8–11). The dictum “once a cesarean always a cesarean” also partly contributed to the increase in the rate of cesarean deliveries (12). However, in the 1970s, some investigators began to reconsider this paradigm, and accumulated data have since supported TOLAC as a reasonable approach in select pregnancies (5, 6, 13–15). Recommendations favoring TOLAC were reflected in increased VBAC rates (VBAC per 100 women with a prior cesarean delivery) from slightly more than 5% in 1985 to 28.3% by 1996. Concomitantly, the overall cesarean delivery rate decreased from 22.8% in 1989 to approximately 20% by 1996 (16).
