Delivery Outcomes in the First 3 Years Following the Clinical Introduction of the Dinoprostone Vaginal Insert in J apan

OBJECTIVE: To evaluate utilization patterns, safety, and delivery outcomes associated with the recently introduced dinoprostone vaginal insert in Japan using multicenter real-world data. METHODS: This two-stage nationwide survey targeted training institutions certified by the Japan Society of Obstetrics and Gynecology. An online questionnaire was sent to 690 institutions to identify facilities eligible for secondary data collection. Participating institutions submitted clinical information for up to 25 consecutive cases in which labor was induced with the insert between January and December 2021. Patient characteristics, insert use, delivery outcomes, and adverse events were summarized. In nulliparas, two subgroup comparisons were conducted: (1) those achieving cervical ripening with the insert alone (P) versus those requiring subsequent mechanical ripening (P to M), and (2) those receiving mechanical ripening before the insert (M to P) versus those receiving the insert first (P to M). RESULTS: Of 973 registered cases from 69 institutions, 947 were eligible for analysis. Nulliparous women accounted for 74.8%. The cesarean section rate was 30.7% overall (36.3% in nulliparas; 14.2% in multiparas). Median time from insert initiation to delivery was 31.6 h. Uterine tachysystole occurred in 18.1% and fetal heart rate abnormalities in 15.8%, but timely management prevented serious outcomes. In subgroup analyses, nulliparas ripened with the insert alone demonstrated shorter induction-to-delivery intervals, lower cesarean and oxytocin-use rates, but more tachysystole. Among cases requiring both methods, the order of ripening techniques did not affect vaginal delivery success. CONCLUSION: This first multicenter real-world evaluation demonstrates that the insert is effective and generally safe for cervical ripening and labor induction in Japan.