Intrapartum intervention rates and perinatal outcomes following induction of labour compared to expectant management at term from an Australian perinatal centre.

BACKGROUND: Induction of labor (IOL) is a common obstetric intervention, yet its impact on intervention rates and perinatal outcomes is conflicting.

AIMS: To evaluate the impact of IOL on intrapartum intervention rates and perinatal outcomes in women with singleton pregnancies at term.

MATERIAL AND METHODS: This was a retrospective, cross-sectional study of term singleton deliveries at the Mater Mother's Hospital in Brisbane, Australia in 2007-2013. The IOL cohort was compared to an expectantly managed group.

RESULTS: Of the final cohort (44 698 women), 64.4% had expectant management and 35.6% had IOL. Multivariate analyses showed that IOL was associated with lower odds of spontaneous vaginal delivery from ≥37 weeks gestation. The risk of emergency caesarean for non-reassuring fetal status was also higher in the IOL cohort at 40 and 41 weeks gestation. For women who were managed expectantly, the highest rate of spontaneous vaginal delivery and the lowest rate of emergency caesareans occurred at 39 weeks gestation. For women who underwent IOL, the nadir emergency caesarean rate and the highest spontaneous vaginal delivery rate was also at 39 weeks. Rates of neonatal intensive car unit admission were higher in the IOL group at 37 weeks (adjusted odds ratio (aOR) 3.11, 95% CI: 2.62-3.68) and 38 weeks (aOR 1.78, 95% CI: 1.55-2.04) and lower at >42 weeks (OR 0.35, 95% CI: 0.14-0.81) respectively.

CONCLUSION: IOL compared to expectant management is associated with lower spontaneous vaginal delivery rates and increased risk of emergency caesarean for intrapartum fetal compromise with broadly comparable perinatal outcomes.