Study on Misoprostol and Dinoprostone for Induction of Labor

In a recent development, the noninferiority of 25-μg misoprostol every four hours to the dinoprostone pessary for cesarean delivery (CD) rates after induction of labour (IOL) at term could not be demonstrated, although results from the study highlighted that the confidence limit of the difference barely exceeded the noninferiority margin. Findings have been published in the American Journal of Obstetrics & Gynecology.

Induction of labor is among the most common procedures for pregnant women. Only a few randomized clinical trials (RCT) with relatively small samples have compared misoprostol to dinoprostone. Although their efficacy appears similar, their safety profiles have not been adequately evaluated and economic data are sparse.

With this in mind, a team of researchers from the Department of Obstetrics and Gynaecology, Paule de Viguier Hospital, France aimed to test the noninferiority of vaginal misoprostol (PGE1) (25 μg) to a slow-release dinoprostone (PGE2) pessary (10 μg) for induction of labor with an unfavorable cervix at term.

Study Design

The study design consisted of an open-label multicenter randomized noninferiority trial at 4 university hospitals of the Research Group in Obstetrics and Gynecology (GROG) between 2012 and 2015. They recruited women with labor induced for medical reasons, a Bishop score ≤ 5 at ≥ 36 weeks, and a cephalic-presenting singleton pregnancy with no prior cesarean delivery. Women were randomly allocated to receive either vaginal misoprostol at 4-hour intervals (25 μg) or a 10-mg slow-release dinoprostone pessary.

Outcomes

• The primary outcome was the total cesarean delivery rate. Noninferiority was defined as a difference in the cesarean delivery rates between the groups of no more than 5%.
• Secondary outcomes included neonatal and maternal morbidity, vaginal delivery < 24 hours after starting the induction process, and maternal satisfaction.

Data Analysis

Data analysis revealed some interesting facts.

• The study included 1674 randomized women. The per-protocol analysis included 790 in each group.
• The total cesarean delivery rate in the misoprostol group was 22.1% (n=175) and in the dinoprostone group, 19.9% (n=157), for a difference between the groups of 2.2% (with an upper-bound 95% confidence limit of 5.6%), P=.092. Results in the intention-to-treat analysis were similar.
• Neonatal and maternal morbidity were similar between groups.
• Vaginal delivery within 24 hours was significantly higher in the misoprostol group (59.3% vs 45.7%, P<.001) as was maternal satisfaction, assessed in the postpartum period by a visual analog scale: mean score: 7.1 (SD 2.4) vs 5.8 (3.1), P<.001.

Conclusion

Observing the results, the research team concluded that "Nonetheless, given the small difference between these cesarean rates and the similarity of neonatal and maternal morbidity rates in this large study, the clinical risk-benefit ratio justifies the use of both drugs."

For full article follow the link: https://doi.org/10.1016/j.ajog.2021.04.226

Primary source: American Journal of Obstetrics & Gynecology