Antenatal corticosteroids: a retrospective cohort study on timing, indications and neonatal outcome.

INTRODUCTION: An antenatal corticosteroid (ACS) delivery interval of 24 h to seven days is commonly referred to as optimal timing. We aimed to investigate whether the ACS delivery interval was associated with the obstetric indication for treatment and with neonatal complications. MATERIAL AND METHODS: The study was a retrospective chart review of clinical data from preterm neonates delivered at the Skåne University Hospital, Lund University, Sweden, from 1 January 2013 to 31 December 2016. The ACS delivery intervals were compared between groups of women with various clinical scenarios and related to neonatal outcomes. RESULTS: The study included 498 preterm neonates from 431 women. One to seven days before delivery, 41% of the women received ACS. Women with preterm prelabor rupture of membranes or vaginal bleeding had a median ACS delivery interval of 7.5 and eight days, respectively, compared with women with maternal/fetal indications or preterm labor (three and two days, respectively) (p < 0.001). Neonates with an ACS delivery interval of more than seven days were at a higher risk of respiratory distress syndrome [odds ratio (OR) 2.00, 95% confidence interval (CI) 1.05-3.79] and moderate or severe bronchopulmonary dysplasia (OR 2.78, 95% CI 1.45-5.33) than were neonates with an ACS delivery interval of one to seven days. CONCLUSION: Optimal timing of ACS treatment varied significantly based on the clinical indication. Women with preterm prelabor rupture of membranes or vaginal bleeding were more likely to have an ACS delivery interval of more than seven days. A prolonged ACS delivery interval was associated with an increased risk of neonatal respiratory morbidity and a prolonged stay in the neonatal care unit, but not with neonatal mortality.