Maternal characteristics and neonatal outcomes of emergency repeat caesarean deliveries due to early-term spontaneous labour onset

Background: The optimal timing of elective repeat caesarean delivery has yet to be determined. One of the reasons to schedule an elective repeat caesarean delivery before 39 weeks gestation is to avoid emergency caesarean delivery due to spontaneous onset of labour. Aims: By ascertaining maternal characteristics and neonatal outcomes associated with early-term onset of spontaneous labour, we aim to determine the optimal timing for each individual repeat caesarean delivery. Materials and Methods: We performed a retrospective analysis of women with repeat caesarean deliveries planned at 38 weeks gestation between 2005 and 2019 at a tertiary referral hospital in Japan. A multivariate logistic regression analysis was adopted to identify independent contributing factors for early-term spontaneous labour onset. We also compared the rate of neonatal adverse events between women who underwent emergency repeat caesarean deliveries due to the onset of early-term labour and the ones who underwent elective repeat caesarean deliveries at 38 weeks. Results: We included 1152 women. History of vaginal deliveries (adjusted odds ratio (AOR), 2.12; 95% confidence interval (95% CI), 1.21–3.74), history of preterm deliveries (AOR, 2.28; 95% CI, 1.38–3.77), and inadequate maternal weight gain during pregnancy (AOR, 1.78; 95% CI, 1.15–2.75) significantly increased the risk of early-term spontaneous labour onset. In terms of occurrence rate of neonatal complications, we found no significant difference between the groups. Conclusion: These maternal factors are significant predictors for early-term labour onset of repeat caesarean deliveries. The onset of early-term labour did not increase the likelihood of neonatal complications.