Assessment of perinatal outcome after sustained tocolysis in early labour (APOSTEL-II trial)

The APOSTEL II trial is a multicentre placebo-controlled study. Pregnant women admitted for threatened preterm labour who have been treated with 48 hours corticosteroids and tocolysis will be eligible to participate in the trial between 26+0 and 32+2 weeks gestational age. They will be randomly allocated to nifedipine (intervention) or placebo (control) for twelve days or until delivery, whatever comes first.Primary outcome is a composite of perinatal death, and severe neonatal morbidity up to evaluation at 6 months after birth. Secondary outcomes are gestational age at delivery, number of days in neonatal intensive care and total days of the first 6 months out of hospital. In addition a cost-effectiveness analysis will be performed. Analysis will be by intention to treat. The power calculation is based on an expected 11% difference in adverse neonatal outcome. This implies that 406 women have to be randomised (two sided test, β 0.2 at alpha 0.05).This trial will provide evidence as to whether maintenance tocolysis reduces severe perinatal morbidity and mortality in women with threatened preterm labour before 32 weeks.Clinical trial registration: http://www.trialregister.nl webcite, NTR 1336, date of registration: June 3rd 2008.Preterm birth is the most common cause of neonatal morbidity and death worldwide [1]. Two thirds of the preterm births occur as a result of spontaneous labour beginning with spontaneous contractions or with preterm rupture of membranes. Preterm birth accounts for approximately 75% of all neonatal deaths and 50% of childhood neurological morbidities [2]. Moreover, it is associated with high immediate and long-term costs after discharge from the hospital [3]. These include costs for special education services and institutionalised care for physically and mentally disabled infants [4]. The prevalence of adverse neonatal outcome is strongly related to gestational age at delivery and declines from 77% at 24-27 weeks to less then 2% at 34 weeks and