1. Elective induction of labour at 39 weeks gestation compared to expectant management was associated with reduced likelihood of 3rd and 4th degree perineal injury, operative vaginal birth, macrosomia, and low APGAR score at 5 minutes.
2. For multiparous women, elective induction was associated with a reduced likelihood of emergency Cesarean section.
3. For nulliparous women, elective induction was associated with an increased likelihood of shoulder dystocia.
Evidence Rating Level: 2 (Good)
Study Rundown: Elective induction of labour refers to induction without a medical indication. Such indications could be maternal or neonatal, including 41 weeks gestation, pre-eclampsia, prelabour rupture of membranes, or poor fetal growth. Although elective induction of labour is associated with higher rates of C-section and adverse outcomes compared to spontaneous labour, the ARRIVE Trial found lower C-section rates and improved neonatal outcomes when comparing elective induction at 39 weeks to expectant management, meaning that labour is induced only when medically indicated. Therefore, this systematic review and meta-analysis aimed to compare neonatal outcomes and complications from labour, between 39-week elective induction and expectant management. The study also aimed to include populations who have previously been excluded from such studies, including women with high BMI and patients attempting vaginal birth after a prior C-section. This review screened observational studies and randomized controlled trials; however, most of the studies ultimately included were retrospective cohorts. Overall, the review found that compared to expectant management, 39-week elective induction was associated with reduced odds of 3rd or 4th degree perineal injury, macrosomia, operative vaginal birth, and low APGAR score at 5 minutes. For multiparous women, there was also a reduced odds of C-section. For nulliparous women, there was an increased odds of shoulder dystocia. Overall, this review generally demonstrated reduced likelihood of labour-related complications and poor neonatal outcomes with 39-week elective induction of labour compared to expectant management.
In-Depth [systematic review and meta-anlaysis]: This review ultimately analyzed 14 eligible studies, including 1 randomized controlled trial, 1 cross-sectional study, and 12 retrospective cohort studies. Altogether, these studies included 1,625,899 women with a singleton pregnancy, 86,555 of underwent induction at 39 weeks. The results showed that compared to expectant management, patients had 37% lower odds of 3rd or 4th degree perineal injury (OR 0.63, 95% CI 0.49-0.81), 13% lower odds of operative vaginal birth (OR 0.87, 95% CI 0.79-0.97), 34% lower odds of macrosomia (OR 0.66, 95% CI 0.48-0.91), and 38% lower odds of low 5-minute APGAR score (OR 0.62, 95% CI 0.40-0.96). For nulliparous women, there were also reductions for postpartum hemorrhage (OR 0.89, 95% CI 0.77-1.02) and emergency C-section (OR 0.75, 95% CI 0.53-1.07) that were nonsignificant. For multiparous women, there was also a 39% lower odds of emergency C-section (OR 0.61, 95% CI 0.38-0.98). And finally, for nulliparous women, there was an increased odds of shoulder dystocia (OR 1.22, 95% CI 1.02-1.46). Overall, this review generally demonstrated reduced likelihood of labour-related complications and poor neonatal outcomes with 39-week elective induction of labour compared to expectant management.
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