Short stature and vaginal dinoprostone as independent predictors of composite maternal-newborn adverse outcomes in induction of labor after one previous cesarean: a retrospective cohort study

Abstract

Abstract Background The rates of labor induction and cesarean delivery is rising worldwide. With the confluence of these trends, the labor induction rate in trials of labor after cesarean can be as high as 27-32.7%. Induction of labor after one previous cesarean (IOLAC) is a high-risk procedure mainly due to the higher risk of uterine rupture. Nevertheless, the American College of Obstetricians and Gynecologists considers IOLAC as an option in motivated and informed women in the appropriate care setting. We sought to identify predictors of a composite of maternal and newborn adverse outcomes following IOLAC. Methods The electronic medical records of women who delivered between January 2018 to September 2022 in a Malaysian university hospital were screened to identify cases of IOLAC. A case is classified as a composite adverse outcome if at least one of these 11 adverse outcomes of delivery blood loss ≥ 1000 ml, uterine scar complications, cord prolapse or presentation, placenta abruption, maternal fever (≥ 38 0C), chorioamnionitis, intensive care unit (ICU) admission, Apgar score < 7 at 5 min, umbilical artery cord artery blood pH < 7.1 or base excess ≤-12 mmol/l, and neonatal ICU admission was present. An unplanned cesarean delivery was not considered an adverse outcome as the practical management alternative for a clinically indicated IOLAC was a planned cesarean. Bivariate analysis of participants’ characteristics was performed to identify predictors of their association with composite adverse outcome. Characteristics with crude p < 0.10 on bivariate analysis were incorporated into a multivariable binary logistic regression analysis model. Results Electronic medical records of 19,064 women were screened. 819 IOLAC cases and 98 cases with composite adverse outcomes were identified. Maternal height, ethnicity, previous vaginal delivery, indication of previous cesarean, indication for IOLAC, and method of IOLAC had p < 0.10 on bivariate analysis and were incorporated into a multivariable binary logistic regression analysis. After adjustment, only maternal height and IOLAC by vaginal dinoprostone compared to Foley balloon remained significant at p < 0.05. Post hoc adjusted analysis that included all unplanned cesarean as an added qualifier for composite adverse outcome showed higher body mass index, short stature (< 157 cm), not of Chinese ethnicity, no prior vaginal delivery, prior cesarean indicated by labor dystocia, and less favorable Bishop score (< 6) were independent predictors of the expanded composite adverse outcome. Conclusion Shorter women and IOLAC by vaginal dinoprostone compared to Foley balloon were independently predictive of composite of adverse outcome.