Intravaginal Administration of Isosorbide Mononitrate for Cervical Ripening in Prolonged Pregnancy: A Randomized Clinical Trial

Objective: Prolonged pregnancies are associated with fetal, neonatal and maternal complications. With regard of the poor consequences, many obstetricians tend to induction of prolonged pregnancies to reduce perinatal morbidity. The present study was performed with aim to evaluate the efficacy and safety of the intravaginal administration of IMN for cervical ripening in prolonged pregnancies.Methods: A total number of 122 pregnant women with prolonged pregnancy who had the inclusion criteria were recruited. Women were assigned to 25μg sublingual misoprostol plus 40 mg isosorbide mononitrate or placebo by a computer generated randomization table. Statistical analysis was done using SPSS software (version 23) and data analysis was performed by T-test, Mann-Whitney and Chi-square test. P≤0.05 was considered significant.Results: The mean time between beginning of cervical ripening to Bishop score > 6 was significantly shorter in the women who received IMN plus misoprostol when compared to misoprostol plus placebo group (P=0.02). The mean time from the beginning of cervical ripening to the beginning of active phase of labor was comparable between two groups (P=0.274). The women receiving misoprostol plus IMN had significantly shorter interval from the beginning of cervical ripening to the time of delivery; indeed there was significant difference in the number of cases in each group that delivered in <24 h after the initial dose for cervical ripening (P=0.044).Conclusion: Isosorbide mononitrate in combination with misoprostol have a promising effect on cervical ripening and labor progress than misoprostol alone in prolonged pregnancy.

Keywords:

Isosorbide mononitrate , Prolonged pregnancy , Cervical ripening