Efficacy of controlled-release dinoprostone vaginal insert for elective induction of labor before due date.

Aim: The induction of labor before due date has recently been proved to reduce the rate of cesarean sections and is not associated with increased risk of adverse perinatal outcomes as compared to expectant management. Controlled-release dinoprostone (PGE₂) vaginal insert has recently been approved for use in Japan. However, evidence regarding its efficacy in cervical ripening and labor induction before due date remains limited. We aimed to compare the efficacy of PGE₂ vaginal inserts and mechanical dilation for labor induction before due date.

Methods: This retrospective cohort study included 206 mothers at 37, 38, and 39 weeks' gestation delivered at our institution between January 2021 and October 2022. Perinatal outcomes, including the success rate of vaginal delivery, were compared between the PGE₂ (n = 46) and metreurynter/laminaria tent (non-PGE₂) (n = 160) groups. The success rate of vaginal delivery was defined as the proportion of women who delivered vaginally within 48 h of initiating oxytocin augmentation.

Results: The success rate of vaginal delivery was significantly higher in the PGE₂ group (37/49, 80.4%) than in the non-PGE₂ group (106/177, 66.2%). Emergency cesarean section related to non-reassuring fetal status was performed with none in the PGE₂ group and with eight (5.0%) in the non-PGE₂ group.

Conclusions: The rate of vaginal delivery was significantly higher in the PGE₂ group for elective labor induction between 37 and 39 weeks. The PGE₂ vaginal insert could increase the success rate of vaginal delivery for elective induction of labor at 39 weeks.