Antenatal Corticosteroid Prophylaxis in Singleton and Multiple Pregnancies.

Background: The effects of antenatal corticosteroids (ANS) in multiple pregnancies are disputed. In this article, we examined whether estimated effects differ in singletons and multiples and in small for gestational age (SGA) preterm infants.

Methods: We studied 17 073 singletons (81% treated with ANS) and 8274 multiples (86% treated) born at 24-33 weeks from the Italian Neonatal Network (2005-2013). We used Poisson regression models with robust variance to estimate adjusted risk ratios (RR) of in-hospital death, severe intraventricular haemorrhage (IVH), periventricular leukomalacia (PVL), and the composite outcome of severe IVH and death.

Results: Mortality was lower among ANS-treated vs. ANS-untreated infants, both in singletons (RR 0.63, 95% confidence interval (CI) 0.58, 0.68) and in multiples (RR 0.85, 95% CI 0.73, 0.98). IVH and the composite outcome of IVH and death, but not PVL, also occurred less frequently among ANS-treated infants. For these outcomes, the effect of ANS was stronger in singletons than in multiples (+35%, +32%, and +22% for death, IVH, and the composite outcome, respectively). Also among SGA infants, singletons, and multiples, ANS-treated infants had lower risk of death, IVH and of composite outcome than untreated ones.

Conclusions: In this large cohort of preterm infants, both multiples and singletons treated with ANS had a lower risk of mortality, of severe IVH, and of composite outcome of IVH and death, both in the overall sample and in SGA infants. Although ANS effect was weaker in multiples, our results support current recommendations to administer ANS prophylaxis in multiple pregnancies at risk of preterm delivery.