Vaginal birth after cesarean in women with pre-labor rupture of membranes at term

Women with a successful vaginal birth after cesarean delivery (VBAC) have less morbidity than women undergoing repeat cesarean delivery. Although several scores and models predict VBAC success, none focus on pregnant women with pre-labor rupture of membranes (PROM). We evaluated different clinical variables that might predict the likelihood of VBAC success in women with PROM.

A retrospective, 5-year study in a large referral center from December 2013 to December 2018. Inclusion criteria were women with singleton pregnancy, at or beyond 37 weeks' gestation, admitted with spontaneous PROM, with one previous cesarean delivery that consented trial of labor. Exclusion criteria were history of two cesarean deliveries, multiple gestations or obstetrical contraindications for TOLAC, including maternal request for repeat cesarean delivery. Variables associated with successful VBA C were identified using multivariate logistic regression.

Of 302 women in the cohort, 74.8% (226/302) delivered vaginally (successful VBAC) and 25.2% (76/302) by repeat CD (failed TOLAC). Multiple logistic regression showed that duration of PROM-to-delivery time was the only significant factor associated with successful TOLAC (78% delivered vaginally within 24 h and 93.3% within 36 h), while none of the other variables (maternal age, gravidity, BMI, gestational and birthweight at delivery, effacement or station at admission, previous indication for cesarean delivery, time interval between previous and current delivery, presence of meconium-stained liquor, and documented temperature >38 °C) were associated with the prediction of successful VBAC.

Women with spontaneous pre-labor PROM and previous cesarean delivery have high success rates of VBAC. The only significant variable associated with successful TOLAC in women with spontaneous PROM at term was the duration of PROM-to-delivery time. Our findings suggest that the success rate of VBAC is likely multifactorial, not-necessarily related to a specific underlying factor, and in the absence of contraindications, a fair trial of labor after cesarean delivery is justified.