Vaginal birth after cesarean in women with no prior vaginal delivery carrying a large for gestational age baby

Background: To study the factors associated with successful labor after cesarean (LAC) among women with no prior vaginal delivery, delivering a large for gestational age (LGA) baby. Methods: A retrospective case-control study at two tertiary medical centers in Israel, including all women undergoing LAC with no prior vaginal delivery during 2010-2020, delivering a singleton LGA newborn. Factors associated with successful vaginal delivery were examined by a multivariable analysis. Results: Overall, 323/505 (64.0%) had a successful LAC. Arrest of labor as the indication for previous CD was less common in the LAC success group [39 (12.1%) vs. 58 (31.9%), P <.001]. The rate of epidural analgesia was higher in the LAC success group [249 (77.1%) vs. 122 (67.0%), P =.014]. The rate of weight centile ≥97th was lower in the LAC success group [64 (19.8%) vs. 51 (28.0%), P =.035], as well as the rate of higher LAC birthweight than previous cesarean birthweight [264 (81.7%) vs. 162 (89.0%), P =.030]. In a multivariable logistic regression analysis, maternal height (aOR [95% CI]:1.09 (1.01, 1.17), P =.014) and epidural anesthesia (aOR [95% CI]:3.68 (1.31, 10.32), P =.013) were the only independent factors associated with LAC success. Conclusions: Among primiparous women undergoing LAC carrying LGA newborns, the vaginal delivery rate is acceptable; however, uterine rupture risk is increased. Epidural administration is a modifiable factor and should be taken into consideration during LAC management.