Use of Nitrous Oxide Donor for Labor Induction in Women With PreEclampsia

The investigators are proposing a double blinded, placebo controlled, randomized clinical trial of patients undergoing induction of labor for preeclampsia. Once the decision to induce will be taken, the participants will be randomized to receive either intravaginal IMN (40mg) or identical appearing placebo placed every 4hrs in the posterior vaginal fornix X 3 doses. IMN or placebo will be discontinued when active labor occurs or when the physician decides to proceed with augmentation with oxytocin or AROM. Participants will be induced using the investigators routine induction agents, Misoprostol (25 mcg every 4 hrs for maximum of 6 doses) and an intra-cervical foley bulb will be inserted with 2nd dose of IMN or placebo. Regarding management of labor, physician decides when to proceed with augmentation with oxytocin or AROM.

Inclusion criteria

• Women older than 18 years at the time of induction of labor with the ability to give informed consent
• Induction of labor for clinical diagnosis of preeclampsia
• Unfavorable cervix (Bishop's score of less than 6)
• Cervical dilation 2cm or less
• Singleton
• Gestational age ≥ 24 weeks
• English speaking

Exclusion criteria

• • Contraindication to vaginal delivery

• Contraindication to misoprostol
• Fetal Demise
• Major fetal anomaly
• Non-english speaking women
• HIV
• Medical conditions requiring assisted second stage
• Category III tracing
• Eclampsia
• Hemolysis Elevated Liver enzymes Low Platelets syndrome
• DIC or active hemorrhage before randomization
• Hypersensitivity to isosorbide mononitrate
• Isosorbide mononitrate should not be used in cases of acute myocardial infarction with low filling pressure, acute circulatory failure (shock, vascular collapse), or hypertrophic obstructive cardiomyopathy (HOCM), constrictive pericarditis, low cardiac filling pressures, aortic/mitral valve stenosis and diseases associated with a raised intra-cranial pressure e.g following a head trauma and including cerebral hemorrhage.
• Isosorbide mononitrate should not be used in patients with severe anemia, severe hypotension, closed angle glaucoma or severe hypovolaemia.
• Isosorbide mononitrate tablets contain lactose and therefore patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.