Risks of induction of labour in uncomplicated term pregnancies

Abstract

Our objective was to evaluate the risks of maternal and perinatal morbidity associated with induction of labour in uncomplicated term pregnancies. We conducted a retrospective cohort study including 7,430 women, not referred from another institution, with a single baby in vertex presentation, and delivering between 38 and 40 weeks of pregnancy. Among these women, 3,546 were excluded for prelabour pregnancy complications. Relative risks (RR), adjusted for parity, were computed to compare 3,353 women who went into labour spontaneously with 531 women whose labour was induced. Induction of labour was found to be associated with a higher risk of caesarean section [RR = 2.4, 95% CI 1.8, 3.4]. Use of non-epidural [RR = 1.5, 95% CI 1.2, 1.8] and of epidural analgesia [RR = 1.4, 95% CI 1.1, 1.7] was more frequent after labour induction. Resuscitation [RR = 1.2, 95% CI 1.0, 1.5], admission to the intensive care unit [RR = 1.6, 95% CI 1.0, 2.4] and phototherapy [RR = 1.3, 95% CI 1.0, 1.6] were more frequent after induction of labour. Results were similar when controlling simultaneously for parity, maternal age, gestational age, year of delivery, birthweight and the physician in charge of delivery in a logistic regression analysis. The results of this study suggests that induction of labour is associated with a higher risk of caesarean section and of some perinatal adverse outcomes. Induction of labour should be reserved for cases where maternal and perinatal benefits outweigh the risk of these complications.