Propranolol Rescue of Prolonged Labor

Over 30% of all cesarean deliveries (CD) performed in the United States are for prolonged labor. Current management strategies to resolve prolonged labor fail up to 50% of the time. The uterus is known to express beta receptors, which when stimulated, cause uterine relaxation. Accordingly, beta blockade has been shown to augment uterine contractility. Prior studies have identified treatment with propranolol to have a possible benefit in the management of prolonged labor. This medication warrants further study to evaluate its effectiveness as an intervention for management of prolonged labor. The study proposal is a double-blinded placebo-controlled randomized of propranolol administered to women with a prolonged labor course. The study hypothesis is that propranolol, administered to women experiencing abnormally prolonged labor, will reduce the rate of cesarean delivery (CD) when compared to women who receive placebo. Eligible participants will be laboring women who are greater than or equal to 16 years of age, greater than or equal to 36 weeks gestation, with a singleton, vertex presenting fetus who are eligible for a vaginal delivery. They must meet one of the following study criteria for prolonged labor: 1) not in active labor (defined as cervical dilation greater than or equal to 6cm) after 12 hours with ruptured membranes and receiving oxytocin, or 2) in active labor (defined as cervical dilation greater than or equal to 6cm) with less than 1cm cervical dilation change over 2 hours. Patients will be randomized to receive either a dose of 2mg of IV propranolol or identical appearing placebo. All patients will be eligible for a maximum of one repeat dose at least 2 hours later if they make less than 2 centimeters of cervical dilation change over 2 hours.