A Pilot Randomized Controlled Trial to Evaluate Isosorbide Mononitrate (IMN) Efficiency for Cervical Ripening Prior to Labor Induction in Iranian Pregnant Women

Our aim was to examine the effect and cost-effectiveness of isosorbide mononitrate (IMN) for outpatient (at home) cervical ripening in Iranian women with term pregnancy. Term pregnant women were randomly selected to receive either  15 mg vaginally administered IMN or placebo. Patients were advised to take the second dose at home 24 h later and return to the hospital for admission after the next 24 h if the onset of spontaneous contraction does not occur. Cervical status, maternal blood pressure, maternal pulse rate, fetal heart rate and various side effects were examined. IMN induced a significant increase in cervical Bishop Score; headache, nausea, and dizziness were seen in 8 of 28 participants of IMN group; although, all had normal vital signs and normal FHR, they had to be hospitalized and receive medication to relieve the unpleasant symptoms. Vaginal administration of 15 mg of IMN induced cervical ripening in term pregnant women.  However, the administration of IMN for cervical ripening is not recommended as it produced headache in significant number of Iranian pregnant women.