Cervical Ripening With Misoprostol vs Isosorbide Mononitrate ; A Parallel -Arm Randomized Controlled Trial

This randomized controlled trial evaluates the effectiveness and safety of misoprostol versus isosorbide mononitrate (IMN) for cervical ripening in prolonged pregnancies (≥41+0 weeks gestation). Favorable cervical status, reflected by a Bishop Score ≥6, is critical for successful vaginal delivery. Participants are low-risk pregnant women at 41+6 weeks with an unfavorable cervix. They are randomized to receive either 25 mcg of vaginal misoprostol or 40 mg of vaginal IMN, administered every 4 hours for up to 3 doses. Cervical status is assessed at regular intervals to determine the achievement of cervical ripening within 40 hours.

The primary outcome is the proportion of participants achieving a Bishop Score ≥6. Secondary outcomes include maternal parameters (labor progression, cesarean section rate, postpartum hemorrhage) and neonatal outcomes (Apgar scores, fetal heart rate tracing, and Doppler indices). The study aims to determine which agent more effectively facilitates cervical ripening and supports favorable delivery outcomes in late-term pregnancies.

Inclusion criteria

• Low-risk primigravidae
• Singleton viable pregnancy
• Cephalic fetal presentation
• Confirmed gestational age ≥ 41+0/7 weeks
• Normal fetal growth pattern
• No signs of labor at the time of enrollment

Exclusion criteria

• High-risk pregnancies
• Body mass index (BMI) > 30 kg/m²
• History of unexplained fetal death
• Oligohydramnios or fetal distress
• Abnormal placentation
• Rh-negative status
• Pre-existing medical conditions or contraindications to labor induction or study drugs
• Fetal abnormalities
• Malpresentation or malposition
• Inadequate pelvimetry
• Participants who developed fetal distress or failed to progress during induction and required emergency cesarean section