Comparison of Nifedipine Versus Indomethacin for Acute Preterm Labor

Overview

The purpose of this research study is to determine the best medication to stop preterm labor. Recent studies have identify nifedipine and indomethacin as the two medications that are most likely to delay delivery for 48 hours, decrease maternal side effects and decrease some complications related to preterm delivery to the neonate. Both of these medications are commonly used to stop pre-term labor, therefore it has become our institution's standard to use these two medications in the setting of preterm labor. There have been limited studies comparing these two medications directly. A total of 450 participants will be asked to participate across all study sites.

There are about 10 million births that occur before 37 weeks (prior to full term gestation) that occur annually worldwide. More than 1 million infants die from complications related to preterm birth. Tocolytics, medications that stop preterm labor, have been well studied. Results regarding prolongation of pregnancy are varied, but tocolytics have been shown to delay delivery for 48 hours, allowing time to administer corticosteroids. ACOG (American Congress of Obstetrics and Gynecologists) recommends giving tocolytics to provide time for corticosteroid administration, transfer to tertiary level care and to allow for magnesium infusion to protect the neonatal brain. Corticosteroid administration when the course is completed (48 hours from first dose) decreases some of the major risks associated with prematurity. Recent meta-analyses have shown of the commonly used tocolytics, calcium channel blockers and prostaglandin inhibitors ranked consistently among the top three medications in several categories including delaying delivery by 48 hours. There have been only two published randomized control studies to date that have directly compared these two tocolytics. These studies lacked power and standardization to provide clinical guidelines. There is a high neonatal mortality and morbidity along with exceedingly high hospital costs associated with complications related to preterm birth, so it is important to intervene with superior medications. Here the investigators propose a multi institutional (based within the University of California system) randomized controlled study to directly compare nifedipine (most commonly used calcium channel blocker) to indomethacin (most commonly used prostaglandin inhibitor). Objective: The Investigator's objective is to compare the prolongation of pregnancy by 48 hours after women are diagnosed with preterm labor prior to 32 weeks gestational age and treated with either nifedipine or indomethacin. Investigators hypothesize that indomethacin will significantly arrest preterm labor by 48 hours in more women compared to nifedipine. The primary outcomes measures will be delaying preterm delivery by 48 hours; secondary outcomes measures will include delay of delivery by 7 days and decreasing delivery before 37 weeks.