TOLAC outcomes after a successful external cephalic version

Abstract

Patients undergoing a trial of labor after successful external cephalic version (ECV) have lower rates of vaginal delivery. The aim of this study was to determine whether patients undergoing a trial of labor after cesarean delivery (TOLAC) after a successful ECV are at risk of poor TOLAC outcomes. A retrospective cohort study was conducted at a single university-affiliated medical centre between the years 2012-2018. Patients who underwent a TOLAC attempt after a successful ECV comprised the study group. Outcomes were compared to patients who underwent TOLAC in a vertex presentation without a history of ECV. The primary outcome was TOLAC success. Secondary outcomes included mode of delivery and adverse neonatal outcomes including 5 minute Apgar score < 7, umbilical cord pH < 7.1. Patients undergoing TOLAC with a history of 2 previous cesarean deliveries were excluded from this study. 7693 patients underwent a TOLAC attempt during the study period. 66 patients had a successful ECV and comprised the study group. Outcomes were compared to 7627 patients undergoing TOLAC who did not have an ECV. There were no significant between-group differences in maternal age (31.6± 4.6 Vs 32.4± 5.3, p< 0.19), parity (4.3±2.4 Vs 4.4±2.6 p=0.81 ), gestational age at delivery (39.4±1.2 Vs 39.4±1.4 p=0.51) or birthweight (3338.0±440.9 Vs 3364.9±442.1 p=0.69). Patients who underwent ECV were just as likely to have a successful TOLAC (87.9% Vs 93.5% OR 0.49 95%CI 0.25-1.12 p=0.07) and did not have an increased risk of operative vaginal delivery (13.6% Vs 8.4% OR 1.74 95% CI 0.8-3.4 p=0.13), 5 minute APGAR score < 7 (0% Vs 0.4% OR 0.16 95% CI 0.03-1.8 p=1.0) or umbilical cord pH < 7.1 (1.5% Vs 0.2% OR 7.6 95% CI 0.3-39.8 p=0.15) compared to the control group. TOLAC after a successful ECV is associated with a high rate of vaginal birth after cesarean (VBAC) without an increased risk of adverse neonatal outcomes.