Impact of labor analgesia on mode of delivery and neonatal outcomes in Japan: A retrospective cohort study

Labor analgesia (LA) is associated with the potential hazard of high-risk delivery, such as cesarean section (CS) and instrumental vaginal delivery (IVD), and adverse neonatal outcomes such as neonatal asphyxia and respiratory distress. The objective was to examine the impact of LA on mode of delivery and neonatal outcomes and to counsel pregnant women about a potentially higher risk and allow them to decide LA or non-LA. This retrospective cohort study containing 5,184 pregnant women analyzed the association between LA and both mode of delivery and neonatal outcomes. LA increased the risk of IVD (Adjusted Odds Ratio [AOR] 3.25, 95% confidence interval [95%CI] 2.51-4.20) but decreased that of CS (AOR 0.52, 95%CI 0.44-0.60). Two factors (advanced maternal age [AOR 1.70, 95%CI 1.33-2.17] and primipara [AOR 4.72, 95%CI 3.30-6.75]) increased the risk of IVD. We should carefully consider the indication of LA for cases with these two factors since LA can increase the risk of IVD and adverse neonatal outcomes.