Impact of timing of antenatal corticosteroid exposure on neonatal outcomes

OBJECTIVE: To evaluate morbidities among neonates with a history of remote antenatal corticosteroid (ACS) exposure compared to those with recent exposure. STUDY DESIGN: This is a retrospective-cohort study of neonates born at 30-33 6/7 weeks gestational age. The primary outcome was newborn respiratory distress syndrome (RDS) defined by the persistent need for oxygen at 24 h of life. Maternal chart review established timing of ACS exposure. Data were stratified by the time interval of ACS administration to delivery: none or <48 h (Incomplete/Unexposed), 48 h to 7 days (Recent) and >7 days (Remote). Perinatal outcomes were compared between groups. RESULTS: Five hundred and twenty-four infants were included: 273 Incomplete/Unexposed, 120 Recent and 131 with Remote ACS exposure. RDS was significantly less frequent with Recent vs. Remote exposure (RR: 1.73 [1.01-3.02]p = 0.04). This finding persisted in a logistic regression model. CONCLUSIONS: Infants delivering more than 1 week after ACS exposure have a higher frequency of RDS than those who deliver within 1 week.