Objective: To determine if an additive effect exists between antenatal corticosteroid administration and postnatal surfactant therapy in the prevention of respiratory distress syndrome (RDS) in preterm infants.
Methods: A randomized, double-blind trial was conducted from April 1990 to June 1994, in which dexamethasone (5 mg every 12 hours for a total of four doses) or saline was given to women at risk for delivery at 24-29 weeks' gestation. At birth, prophylactic surfactant was administered to all study infants. Main outcome measures were RDS occurrence and severity. Secondary clinical end points included broncho-pulmonary dysplasia, pneumothorax, patent ductus arteriosus, necrotizing enterocolitis, retinopathy, intraventricular hemorrhage, and death.
Results: Seventy-five of the 124 randomized subjects delivered 96 infants within the studied gestational age range (dexamethasone, n = 54; placebo, n = 42). Similar maternal demographics and obstetric complications were noted between study groups. A greater proportion of infants were delivered from multi-fetal gestations in the dexamethasone cohort (26 of 54 versus 12 of 42 newborns; P = .05). There were no significant differences in the occurrence or severity of RDS between the dexamethasone and placebo infants (none or mild, 67 versus 67%; moderate, 24 versus 26% severe, 9 versus 7%, respectively), or differences in any of the secondary clinical outcomes. The study size was sufficient to exclude a 50% reduction in RDS incidence as a consequence of dexamethasone exposure. An analysis restricted to singletons (dexamethasone, n = 28; placebo, n = 30) revealed similar overall occurrence of intraventricular hemorrhage (12 of 28 versus ten of 30; P = .63), but significantly fewer grade 3 and 4 intraventricular hemorrhages in dexamethasone-exposed neonates (two of 12 versus six of ten; P = .048).
Conclusion: Antenatal dexamethasone does not appear to decrease the incidence or severity of RDS in surfactant-treated infants delivered at 24-29 weeks' gestation, but may be associated with reduced severity of intraventricular hemorrhages in surfactant-treated singletons in this gestational age range.
(C) 1996 The American College of Obstetricians and Gynecologists