Background: Iatrogenic induction of labor has influenced greatly the process of childbirth. Many ways of inducing labor have been studied and practised in the past. Pharmacological stimuli have surpassed mechanical methods in many aspects for inducing labor, although there seems to be a renaissance for the catheter induction in the last years. Dinoprostone (prostaglandin E2) is currently the most frequently used licensed pharmaceutical in this field. Misoprostol, a prostaglandin E1 analogon, is used as either oral or vaginal tablets in many countries off-label for labor induction. Its effectiveness and side effects differ from Dinoprostone, with special regards to its side effects. Especially the higher risk of tachysystole and uterine rupture, have given Misoprostol a slightly doubtful reputation, which may be redrafted now due to a new application mode. According to the latest evidence, a 200 g Misoprostol slow-release vaginal insert might be a viable alternative to conventional methods of labor induction. Therefore, a comparison between this new Misoprostol-product and the already established labor induction protocol at the Department of Obstetrics and feto-maternal Medicine regarding maternal and neonatal outcome shall further elucidate its possible risks and benefits.
Objective: The aim of this study was to compare the effectiveness and use of Misoprostol vaginal inserts against Dinoprostone vaginal tablets for labor induction at the Department of Obstetrics and feto-maternal Medicine at the Medical University of Vienna.
Study Design: This retrospective data analysis evaluated the efficacy and safety of the 200g Misoprostol vaginal insert for induction of labor in comparison to the standard protocol used for labor induction so far at the University Clinic of Obstetrics and Gynecology in pregnant women apart from 37+0 weeks of gestational age. The main outcome parameter was the comparison in time to vaginal delivery and time to any delivery between the two compared patient groups. 120 patients induced with a 200g Misoprostol vaginal insert were compared with 204 patients induced with a 10mg Dinoprostone vaginal insert.
Results: The use of the Misoprostol vaginal insert did not result in a significantly shorter time interval in achieving either any or a vaginal delivery than the Dinoprostone insert. The amount of cesarean sections, operative deliveries, admittances to the NICU, patients in need of anesthesia, patients in need of an episiotomy, and patients that developed fever showed no significant discrepancies between both groups. Gestational ages at delivery, APGAR scores, pH values, and base excesses were insignificantly different in both groups. Misoprostol caused significantly more overstimulations of the uterus than Dinoprostone.
Conclusion: Outcomes between Misoprostol and Dinoprostone were distributed approximately even. Patients in the Misoprostol group had significantly lower Bishop scores prior to induction, were significantly less multiparous and showed significantly more overstimulations of the uterus than Dinoprostone. The time to any delivery as well as the time to vaginal delivery did not differ significantly between the two compared patient groups.