Prophylactic oral nifedipine to reduce preterm delivery: a randomized controlled trial in women at high risk.

Abstract

To establish the efficacy of prophylactic nifedipine vs. placebo in reducing spontaneous preterm delivery in asymptomatic women at high risk for preterm delivery. Prospective multicentric randomized double-blind study. Tertiary care centre, University Hospitals of Brescia and Torino, Italy. Eighty-seven singleton pregnancies without uterine contractions and ultrasonographic cervical length of ≤25mm at 24-32weeks, at risk for preterm delivery, with longitudinal follow up in our Preterm Prevention Clinic. Selection was done on the basis of ultrasonographic cervical length; 43 women were randomized to receive placebo and 44 to receive nifedipine. Primary end point: spontaneous preterm delivery <37weeks in nifedipine vs. placebo. delivery <32weeks, maternal side effects, neonatal complications, admissions to the Neonatal Intensive Care Unit and randomization/delivery time in nifedipine vs. placebo. There was no trend towards a lower risk of spontaneous preterm delivery, neither at <37weeks of nifedipine vs. placebo (11.4% vs. 19.0%; p=0.320), or <32weeks (2.3% vs. 2.4%; p=0.973). Nifedipine reduced spontaneous preterm delivery <37weeks (p=0.015) in the multiparous women by stratified analysis for parity. SECONDARY OUTCOMES between the groups did not differ except for a higher percentage of maternal side-effects in the nifedipine group (31.8%) vs. placebo (11.9%) (p<0.05). Subgroup analysis showed a borderline (p=0.047) lower percentage of spontaneous preterm delivery in women with a ultrasonographic cervical length of <20mm in the nifedipine group. Prophylactic nifedipine in asymptomatic women at high risk for preterm delivery had a positive effect on the rate of spontaneous preterm delivery <37weeks in multiparous women.