Effect of maintenance tocolysis with nifedipine in threatened preterm labor on perinatal outcomes: A randomized controlled trial

textabstractImportance: In threatened preterm labor, maintenance tocolysis with nifedipine, after an initial course of tocolysis and corticosteroids for 48 hours, may improve perinatal outcome. Objective: To determine whether maintenance tocolysis with nifedipine will reduce adverse perinatal outcomes due to premature birth. Design, Setting, and Participants: APOSTEL-II (Assessment of Perinatal Outcome with Sustained Tocolysis in Early Labor) is a double-blind, placebo-controlled trial performed in 11 perinatal units including all tertiary centers in the Netherlands. From June 2008 to February 2010, women with threatened preterm labor between 26 weeks (plus 0 days) and 32 weeks (plus 2 days) gestation, who had not delivered after 48 hours of tocolysis and a completed course of corticosteroids, were enrolled. Surviving infants were followed up until 6 months after birth (ended August 2010). Intervention: Randomization assigned 406 women to maintenance tocolysis with nifedipine orally (80 mg/d; n=201) or placebo (n=205) for 12 days. Assigned treatment was masked from investigators, participants, clinicians, and research nurses. Main Outcome Measures: Primary out