Antenatal corticosteroids and outcomes of small for gestational age infants born at 24–31 gestational weeks: a population-based propensity score matching analysis

Purpose To evaluate the effect of antenatal corticosteroid (ACS) treatment on neonatal outcomes in small for gestational age (SGA) infants born at 24–31 gestational weeks compared with non-SGA infants. Methods A population-based retrospective study was conducted that analyzed clinical data from the Neonatal Research Network of Japan database, which enrolls neonates born at < 32 gestational weeks and weighing 1500 g or less ( n = 22,414). Propensity score matching (with the ratio of ACS to no-ACS groups of 1:1) was performed in SGA ( n = 7028) and non-SGA ( n = 15,386) infants, respectively. Univariate logistic and interaction analyses were performed to compare the short-term neonatal outcomes of infants with and without ACS treatment in utero. Results In the SGA and non-SGA infants, ACS treatment significantly reduced in-hospital mortality (odds ratio 0.67 95% confidence interval [0.50–0.88] and 0.62 [0.50–0.78], respectively), respiratory distress syndrome (0.77 [0.69–0.87] and 0.63 [0.58–0.68], respectively), and composite adverse outcomes (0.73 [0.58–0.91] and 0.57 [0.50–0.65], respectively). ACS treatment also significantly reduced intraventricular hemorrhage (grade III/IV), periventricular leukomalacia, and sepsis in the non-SGA infants, but not in the SGA infants. However, interaction analyses revealed no significant differences between the SGA and non-SGA infants in the efficacy of ACS treatment on short-term outcomes except for respiratory distress syndrome. Conclusions ACS treatment was associated with beneficial effects on mortality, respiratory distress syndrome, and adverse composite outcomes in extremely and very preterm SGA infants, with similar efficacy on all neonatal outcomes except for respiratory distress syndrome observed in the non-SGA infants.