Comparison of vaginal misoprostol, laminaria, and isosorbide dinitrate on cervical preparation and labor duration of term parturient: a randomized double-blind clinical trial.

Background: Cervical ripening plays an important role in successful labor induction.

Objective: This study aimed to compare the effects of misoprostol, laminaria tent, and isosorbide dinitrate (ISDN) on cervical ripening.

Methods: This double-blind three-armed clinical trial was conducted at Shahidan Mombini Teaching Hospital in Sabzevar, Iran, in 2016 on 96 singleton term pregnant women. Participants were randomly allocated to receive either two 20-mg ISDN tablets vaginally every 4 hours for a maximum of three doses or 25 mcg misoprostol vaginally every 6 hours for a maximum of two doses or laminaria tent for a maximum of 12 hours. The method of randomization was covariate adaptive randomization and the primary outcome measures were Bishop Score changes and labor duration. SPSS software version 18 was used for statistical analyses. Kruskal-Wallis, chi-square and ANOVA tests were applied for data analyses.

Results: Bishop Score changes were higher in the misoprostol group than in the two other groups (p=0.014). Time from start of medication to active phase of labor and delivery were 6.22±3.11 and 11.78±5.3 minutes in the misoprostol group, 11.25±3.07 and 17.62±4.07 minutes in the laminaria group, and 10.12±3.48 and 17.37±4.79 minutes in the ISDN group respectively (p<0.001). Cesarean rate was higher in the misoprostol group than the two other groups (p=0.016). No significant differences were observed between the study groups in terms of Apgar score and meconium-stained amniotic fluid.

Conclusions: Use of misoprostol results in more improvement of Bishop Score and reduced length of labor phases in comparison to laminaria tent and ISDN.

Trial Registration: The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the Irct ID: IRCT2016050527643N2 in the Iranian Registry of Clinical Trials IRCT2015040921670N1.

Funding: The authors received no financial support for the research, authorship, and/or publication of this article.