Induction of labor at term using isosorbide mononitrate simultaneously with dinoprostone compared to dinoprostone treatment alone: A randomized, controlled trial

Objective We aimed to determine whether isosorbide mononitrate (IMN) given simultaneously with dinoprostone in term pregnancies is superior to dinoprostone alone to promote delivery. Study design One hundred and twenty nulliparous women at term were randomly assigned to receive per vaginam IMN 40 mg or placebo in addition to 3 mg dinoprostone 2 times daily for up to 2 days. Analysis was by intention to treat. Results Baseline characteristics of both groups were comparable. The induction to delivery intervals did not differ between the IMN and the placebo group (26.4 ± 14.4 vs 23.4 ± 14.8 hours, P = .408). IMN resulted in more headache compared to placebo (32/55 [58.2%] vs 2/55 [3.6%], P< .001). Conclusion Vaginally administered IMN does not play a role in promoting delivery in term pregnancy if given at the same time as dinoprostone. This might reflect its relaxant effect on the uterine fundus, which may overcome its cervical softening effect.