Trial of labor after cesarean delivery with a lower-segment, vertical uterine incision: is it safe?

OBJECTIVE: Our purpose was to assess maternal and perinatal outcomes associated with a trial of labor and attempted vaginal birth after prior low-segment vertical cesarean delivery.

STUDY DESIGN: During a 10-year period in a single tertiary hospital, all patients with a prior low-segment uterine incision (whether vertical or transverse) were considered candidates for a trial of labor in the absence of other contraindications or patient refusal. Among the 1137 women who underwent low-segment vertical cesarean delivery, 262 were subsequently delivered of 322 live-born infants, and 174 (54%) of them were identified retrospectively as having attempted vaginal birth. The maternal and perinatal outcomes of patients who did or did not undergo a trial of labor were analyzed and compared.

RESULTS: No significant differences between the two patient groups were observed regarding demographic characteristics, antepartum complications, gestational age at delivery (mean 37.4 weeks), birth weight, and cord pH at delivery. Vaginal delivery was accomplished successfully in 144 of 174 (83%) patients who underwent a trial of labor. Abdominal delivery was necessary for 17 mothers with labor disorders and 13 with suspected fetal distress. Postpartum hemorrhage occurred more often in the trial of labor group (7/174 [4.0%] vs 2/148 [1.4%], p not significant), but endometritis developed significantly more often in patients with elective repeat cesarean delivery (16.9% vs 6.3%, p = 0.006). Rupture of the low-segment vertical cesarean scar occurred in 2 patients during a trial of labor (1.1%) versus none in the elective repeat cesarean group. Neither mother experienced fetal extrusion or adverse maternal or fetal sequelae. Frequency of serious neonatal complications (8.1% vs 10%) and neonatal mortality (1.7% vs 2.0%) were similar between groups. All neonatal deaths were a result of extreme prematurity or congenital anomalies.

CONCLUSIONS: Our experience indicates that a mother with a prior low-segment vertical cesarean delivery can undertake a trial of labor with relative maternal-perinatal safety. The likelihood of successful outcome and the incidence of complications are comparable to those of published experience with a trial of labor after a previous low-segment transverse incision.