Practices in induction of labor for medical termination of pregnancy or intra uterine fetal death are controverted. DILAPAN-S dilators are often used as an adjunction of oral prostaglandins to reduce the time of delivery, but protocols may differ between practicians. At the University Hospital of Saint-Etienne, the DILAPAN-S were applied the evening before induction until 2020, and the same day as misoprostol intake since 2022.

To evaluate these two protocols of induction of labor with DILAPAN-S, on the day before and on the same day as prostaglandins, on the reduction of time of labor.

Retrospective, single-center, before-and-after observational study carried out in the Department of Obstetrics and Gynecology at the University Hospital of Saint-Etienne between 2018–2020 and 2022–2024. Patients were respectively included in the ″Day-1″ or in the ″Day 0″ group. The primary endpoint was the time of labor in each group, measured in hours. 205 patients were included, 97 in the ″Day-1″ and 108 in the ″Day 0” group. The analysis of the primary outcome was per-protocol.

The time interval between the first dose of misoprostol and delivery was on average 7h25 ± 7h41 in the ″Day -1″ group and 10h35 ± 7h18 in the ″Day 0″ group, which means a difference of 3h10 (p < 0,0001). Duration in delivery room as well as duration of epidural analgesia were shorter in the ″Day -1″ group, but duration of hospitalization and obstetrical complication were lower in the ″Day 0″ group. The proportion of patients experiencing a labor duration longer than 12 hours was significantly higher in the ″Day 0” group.

The use of DILAPAN-S dilators the day before a misoprostol induction reduces the time of labor in comparison as DILAPAN-S used concomitate with prostaglandins in a situation of TOP or IUFD, but it increases the duration of hospitalization. The reduction of 3 hours is not clinically significant. Other studies are needed to explore the possibility of outpatient used and the women's experiences.