Should patients with documented fetal lung immaturity after 34 weeks of gestation be treated with steroids?

Objective The purpose of this study was to determine whether corticosteroid administration after 34 weeks of gestation is associated with improved neonatal outcome in the presence of fetal lung immaturity. Study Design We conducted a retrospective cohort study of women who underwent amniocentesis to determine fetal lung maturity from 34-37 weeks of gestation. Patients with negative results (167 women) received steroids based on physician preference and were categorized into 2 groups: study group treated with betamethasone (n = 83 women) and control group in which patients did not receive betamethasone therapy (n = 84 women). The 2 groups were compared with respect to neonatal outcomes. Composite neonatal morbidity was defined as the presence of respiratory distress syndrome, transient tachypnea of the newborn infant, or the need for respiratory support. Results The rate of composite neonatal morbidity was significantly lower among infants who were exposed to steroids compared with the control group (8.4% vs 21%; P = .02). Multiple regression analysis revealed that corticosteroid administration was associated independently with the composite morbidity outcome. Conclusion Antenatal steroid administration after 34 weeks of gestation is associated with improved neonatal outcome and should be considered when fetal lung immaturity is documented.