Antenatal corticosteroid treatment in singleton, small-for-gestational-age infants born at 24-31 weeks' gestation: a population-based study.

Objective: To assess the impact of antenatal corticosteroid therapy on mortality and severe morbidities in preterm, small-for-gestational-age (SGA) neonates compared with preterm non-SGA neonates.

Design: Population-based study.

Setting/population: Israel National Very Low Birth Weight infant database from 1995-2012.

Methods: Singleton infants of 24-31 weeks' gestation, without major malformations. Antenatal corticosteroids were considered either any treatment or no treatment.

Main Outcome Measures: Univariate and multivariable logistic regression analyses were performed to assess the effect of antenatal corticosteroids on neonatal mortality and a composite adverse outcome of mortality or severe neonatal morbidity.

Results: Among the 10 887 study infants, 1771 were SGA. Of these, 70.4% of SGA and 66.7% of non-SGA neonates were exposed to antenatal corticosteroids. Among SGA neonates, antenatal corticosteroids were associated with decreased mortality (32.2 versus 19.3%, P < 0.0001) and composite adverse outcome (54.1 versus 43.4%, P < 0.0001), similar to the effect in non-SGA neonates (mortality 26.7 versus 12.2%, P < 0.0001; composite outcome 50.5 versus 34.6%, P < 0.0001). Multivariable logistic regression analyses demonstrated a 50% reduction in mortality risk among SGA and 57% reduction in non-SGA neonates exposed to corticosteroids [OR = 0.50, 95% confidence interval (95% CI) 0.39-0.64 and OR = 0.43, 95% CI 0.38-0.47, respectively], P-value for interaction = 0.08. Composite adverse outcome risk was significantly reduced in SGA (OR = 0.67, 95% CI 0.54-0.83) and non-SGA infants (OR = 0.57, 95% CI 0.52-0.63), P-value for interaction = 0.04.

Conclusions: Antenatal corticosteroids significantly reduced mortality and severe morbidities among preterm SGA neonates, with slightly a less pronounced effect compared with non-SGA preterm infants. Antenatal corticosteroids should be given to fetuses suspected of intrauterine growth retardation, at risk for preterm delivery, in order to improve perinatal outcome.

Tweetable Abstract: Antenatal steroids reduced mortality and severe morbidities among singleton, preterm SGA neonates.