Castor oil plus sweeping membrane maneuver versus oral misoprostol for labor induction: a prospective observational study

Labor induction is a common procedure in obstetric practice, required to terminate pregnancy in several clinical conditions. Oral prostaglandins are frequently used, but require close monitoring of maternal-fetal well-being. Combination of oral castor oil administration plus membrane sweeping maneuver could represent an initial strategy, but its comparative effectiveness and resource implications require further evaluation. A prospective observational study was conducted on 169 term pregnant women indicated for labor induction: 100 received 60 mL oral castor oil plus membrane sweeping (combined strategy); 69 received oral misoprostol. Primary outcome was active labor onset within 24 h; other outcomes included maternal-fetal safety parameters, induction-to-delivery time and secondary medical interventions. Labor onset within 24 h was achieved in 54/100 patients (54.0%) of the combined strategy group versus 37/69 patients (53.6%) of the misoprostol group. The crude risk difference was + 0.38% points (95% CI − 14.51 to + 15.37), while the adjusted risk difference was − 2.59% points (95% bootstrap CI − 17.97 to + 14.31). Given a no difference detected in induction-to-delivery interval, the combined strategy was associated with a significantly less use of secondary medical interventions (oxytocin use, amniorexis, epidural analgesia). Overall, delivery mode and neonatal outcomes were comparable; the misoprostol group had a higher incidence of meconium-stained amniotic fluid (5,0% versus 13,0%), but the association was exploratory. Crossover to misoprostol was described as a treatment pathway and was not used to infer comparative efficacy. This prospective observational study did not detect a difference in the proportion of women entering active labor within 24 h between the two initial strategies; however, the study was not designed to establish equivalence or non-inferiority. Lower use of some intrapartum interventions was observed in the combined strategy group, but residual confounding cannot be excluded. Larger randomized studies should assess clinical outcomes, safety and costs.