A comparative study on the efficacy of nifedipine and indomethacin for prevention of preterm birth as monotherapy and combination therapy: a randomized clinical trial

Abstract

Introduction: Preterm delivery is an important issue in obstetrics, which is the most common cause of neonatal mortality and morbidity. Therefore, finding a way to prevent it is always under serious concern.Objective: The study aimed to compare the efficacy of two tocolytic agents, nifedipine and indomethacin, for inhibiting preterm uterine contractions as monotherapy and combination therapy.Materials and methods: A double-blind randomized clinical trial was performed on pregnant women with gestational age of 26–34 weeks of pregnancy who referred to hospital for preterm labor. They were randomly assigned to three groups. Indomethacin plus placebo, nifedipine plus placebo, and a combination of indomethacin and nifedipine were administered to the three groups. Inhibiting contractions for 2 hours and prevention of delivery for 48 hours and 7 days were evaluated. Also, duration of pregnancy, the number of preterm births, and the interval between entering the study and delivery were compared between three groups.Results: One hundred fifty women were eligible for the study. Two women in the nifedipine group and one woman in the combined group were excluded from the study because of hypotension. The women of the three groups did not have significant difference according to age, BMI, gravidity, parity, Bishop score, gestational age, and the number of contractions at entering the study. Thirty-six women (72%) in the indomethacin group, 36 women (72%) in the nifedipine group, and 41 women (89.4%) in the combination group had stopped contractions within the first 2 hours of intervention (p = .002). Inhibiting contractions for 48 hours (p = .003), inhibiting contractions for 7 days (p = .021), gestational age at birth (p = .001), number of pregnancies more than 37 weeks (p = .007), and neonatal weight (p = .020) were significantly more in the combination group.Conclusion: Combination therapy with nifedipine and indomethacin was more effective than monotherapy with either of these two medications for inhibiting preterm labor, delaying delivery, and prolongation of the duration of pregnancy.