Maternal and neonatal outcomes after induction of labor: a population-based study.

Objective: To evaluate maternal and neonatal outcomes at and beyond term associated with induction of labor compared to spontaneous onset of labor stratified by week of gestational age.

Methods: In this retrospective cohort study, data form 402,960 singleton pregnancies from the Austria Perinatal Registry were used to estimate odds ratios of secondary cesarean delivery, operative vaginal delivery, epidural analgesia, fetal scalp blood testing, episiotomy, 3rd/4th-degree lacerations, retained placenta, 5-min APGAR <7, umbilical artery pH <7.1, and admission to neonatal intensive care unit. Multivariate logistic regression models based on deliveries with gestational age ≥37 + 0 were applied for adjustment for possible confounders.

Results: Induction of labor was associated with increased odds for cesarean delivery (adjusted OR; 99% confidence interval: 1.53; 1.45-1.60), operative vaginal delivery (1.21; 1.15-1.27), epidural analgesia (2.12; 2.03-2.22), fetal scalp blood testing (1.40; 1.28-1.52), retained placenta (1.32; 1.22-1.41), 5-min APGAR <7 (1.55; 1.27-1.89), umbilical artery pH <7.1 (1.26; 1.15-1.38), and admission to neonatal intensive care unit (1.41; 1.31-1.51). In a subgroup of induction of labor with the indication, "post-term pregnancy" induction was similarly associated with adverse outcomes.

Conclusions: In Austria, induction of labor is associated with increased odds of adverse maternal and neonatal outcomes. However, due to residual confounding, currently, no recommendations for treatment can be derived.