Randomized Clinical Trial of Pre-Induction Cervical Ripening by Isosorbide Mononitrate at Term Prgnancy

Abstract

Background and objective: Induction of labor is deemed successful when it initiates uterine contractions, progressively dilates and effaces the cervix, and leading to the normal vaginal birth of the baby with no maternal or fetal complications . Because the success of induction is related to cervical ripening, artificial cervical ripening before labor induction is used when the cervix is unfavorable to reduce the associated risk of cesarean delivery. The objective is to test the efficacy and safety of Isosorbide mononitrate for cervical ripening before the induction of labor at term, from. Methods: A randomized clinical trial was conducted in maternity hospital in Sulaimani, from the 1st of January 2008 to the 1st of July 2008. Forty six pregnant women with gestational age of (37- 42) weeks, singleton, viable, low risk pregnancy and cephalic presentation with Bishop score of less than 6 were selected for induction of labor for various causes. Forty eight hours before induction, 40 mg IMN (2 tablets of 20 mg) were inserted vaginally up to 3 doses 16 hours apart. Results: It was found that the mean ± SD Bishop score before IMN administration was (1.95 ± 1.5), while after IMN was (6.65± 3.06) P-value = 0.0001. Sixteen cases (35.6%) went to active labor. The mean ± SD time of admission in labor room was (5.06 ± 3.8) hours.43 cases (93.5%) needed oxytocin for their inductions & eighteen cases (39.1%) were delivered by C/S. There was no significant change in FHR before and after IMN and all women delivered active babies with normal Apgar score. The main side effect was headache which was experienced by 31cases (63.4%). Conclusion: IMN is an effective and safe agent for cervical ripening which can be used as an outpatient basis.