Risk factors for cesarean section and instrumental vaginal delivery after successful external cephalic version

Aim of this article is to examine if we could identify factors that predict cesarean section and instrumental vaginal delivery in women who had a successful external cephalic version. We used data from a previous randomized trial among 25 hospitals and their referring midwife practices in the Netherlands. With the data of this trial, we performed a cohort study among women attempting vaginal delivery after successful ECV. We evaluated whether maternal age, gestational age, parity, time interval between ECV and delivery, birth weight, neonatal gender, and induction of labor were predictive for a vaginal delivery on one hand or a CS or instrumental vaginal delivery on the other hand. Unadjusted and adjusted odds ratios were calculated with univariate and multivariate logistic regression analysis. Among 301 women who attempted vaginal delivery after a successful external cephalic version attempt, the cesarean section rate was 13% and the instrumental vaginal delivery rate 6%, resulting in a combined instrumental delivery rate of 19%. Nulliparity increased the risk of cesarean section (OR 2.7 (95% CI 1.2-6.1)) and instrumental delivery (OR 4.2 (95% CI 2.1-8.6)). Maternal age, gestational age at delivery, time interval between external cephalic version and delivery, birth weight and neonatal gender did not contribute to the prediction of failed spontaneous vaginal delivery. In our cohort of 301 women with a successful external cephalic version, nulliparity was the only one of seven factors that predicted the risk for cesarean section and instrumental vaginal delivery.