Induction of Labor in Morbidly Obese Patients

The rate of IOL continues to increase, from about 10% in 1990 to 23% in 2018. Patients with BMI >40 are at increased risk for failed IOL and needing a CD. Studies show that morbidly obese patients require higher doses of pitocin and multiple agents to achieve vaginal delivery, but optimal dosing of misoprostol has not been studied as well. Increasing the rate of vaginal delivery in this population will help decrease risk of surgical morbidity.

The investigators plan to conduct a randomized controlled double blinded trial. Patients who are scheduled for induction of labor after 34 weeks gestation, have a BMI >40, and meet all study inclusion criteria will be approached by research personnel during their outpatient appointments. Participants will be randomized to either receive 25 mcg vaginal misoprostol every 4 hours or 50 mcg vaginal misoprostol every 4 hours.

Inclusion criteria

• Morbidly obese (BMI ≥ 40 kg/m2) at admission for induction of labor
• Speaks English or Spanish
• Gestational age between 34 weeks and 0 days and 42 weeks and 6 days
• Age 18 years old or older
• Viable, single, cephalic fetus
• Intent to proceed with cervical ripening - cervical exam: dilation < 5 cm
• Contractions < 5 per 10 minutes

Exclusion criteria

• History of cesarean delivery
• Contraindication to prostaglandin administration (significant myomectomy, prior cesarean delivery)
• Contraindication to vaginal delivery (placenta previa, vasa previa, HIV with high viral load)
• Contraindications to labor (cardiac, neurosurgical, need for cesarean)
• Age < 18yo
• Fetal growth restriction with abnormal umbilical artery Doppler indices
• Cervical dilation >5 cm
• Contractions >5 per 10 minutes
• Significant vaginal bleeding with concern for placental abruption
• Non-reassuring fetal status or fetal heart rate decelerations
• Fetal demise or major fetal anomaly
• Inability to give consent