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

OBJECTIVE: To establish the efficacy of prophylactic nifedipine vs placebo in reducing spontaneous preterm delivery (SPD) in asymptomatic women at high risk for preterm delivery. DESIGN: Prospective multicentric randomized double-blind study. SETTING: Tertiary Care Centre, University Hospitals of Brescia and Torino, Italy. POPULATION: Eighty-seven singleton pregnancies without uterine contractions and ultrasonographic cervical length (UCL) of ≤25mm at 24-32 weeks, at risk for preterm delivery, with longitudinal follow-up in our Preterm Prevention Clinic. METHODS: Selection was done on the basis of UCL; 43 women were randomized to receive placebo and 44 nifedipine. MAIN OUTCOME MEASURES: Primary end point: SPD <37 weeks in nifedipine vs. placebo. Secondary outcomes: delivery <32 weeks, maternal side-effects, neonatal complications, admissions to the Neonatal Intensive Care Unit and randomization- delivery time in nifedipine vs. placebo. RESULTS: There was no trend towards a lower risk of SPD, neither at <37weeks of nifedipine vs. placebo (11.4% vs. 19.0% p=0.320), or <32 weeks (2.3% vs. 2.4% p=0.973). Nifedipine reduced SPD <37 weeks (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 SPD in women with a UCL of <20mm in the nifedipine group. CONCLUSIONS: Prophylactic nifedipine in asymptomatic women at high risk for preterm delivery had a positive effect on the rate of SPD <37 weeks in multiparous women. This article is protected by copyright. All rights reserved.