The risk of uterine rupture after vaginal birth after cesarean delivery (VBAC) is small, but the consequent maternal and fetal morbidity is potentiality very serious. The investigators sought to identify factors associated with uterine rupture in 972 attempts at VBAC made by 936 women at a single institution in the years 1996-1999. Six attempts involved twin gestations. Vaginal delivery took place in 72% of cases. There were 33 uterine ruptures at the site of previous cesarean delivery (3.4%). All but 5 ruptures were symptomatic. Two ruptures were in women having 2 past cesarean deliveries.
There were no differences between the women with and those without uterine rupture in mean gestational age. Women having a successful VBAC previously were less likely to have a symptomatic uterine rupture. Induction was more frequent in patients with uterine rupture, and they were much likelier to have undergone cervical ripening before induction. The odds ratio (OR) for symptomatic rupture after preinduction cervical ripening was 3.92. When a Foley catheter was used for preinduction cervical ripening, the OR for uterine rupture was 3.67. All ruptures in women having preinduction cervical ripening developed uterine rupture during active labor. Women having preinduction cervical ripening were significantly less likely than other women to deliver vaginally (46.7% vs. 76.95%). Al but 2 women with uterine rupture were delivered by cesarean section. The only intrapartum fetal death occurred in a woman with symptomatic uterine rupture who had fetal expulsion at the time of emergency cesarean delivery. Apgar scores at 1 minute, but not at 5 minutes, were lower in cases of symptomatic uterine rupture. Fetuses born after symptomatic uterine rupture were likelier to be admitted to neonatal intensive care. No woman required a blood transfusion or hysterectomy.
Women attempting VBAC have a high rate of symptomatic uterine rupture after preinduction cervical ripening, and the risk-benefit ratio would seem to discourage this practice. This is especially the case when considering the low rate of successful vaginal delivery. Women must know of the risks involved, and elective repeat cesarean delivery should be carefully considered as an effective alternative to VBAC.
Department of Obstetrics and Gynecology, Christiana Care Health Services, Newark, Delaware
Am J Perinatol 2004;21:217-221