Objective: We hypothesized that a pulsed course of dexamethasone would result in better linear growth than a 42-day reducing course in preterm infants at risk for chronic lung disease of prematurity.

Study design: Forty infants with a birth weight of ≤1,250 g who required mechanical ventilation at 7 days of age were randomly assigned to a repeatable 3-day pulse course of dexamethasone commencing immediately or a 42-day (long) course commencing at 14 days of age if they still required mechanical ventilation and supplemental oxygen. The primary outcome measure was linear growth at 36 weeks’ postmenstrual age measured by knemometry.

Results: There was no difference in lower leg length at 36 weeks’ postmenstrual age. Infants receiving the pulse course had lower rises in blood pressure, less myocardial hypertrophy, and less adrenal suppression. However, more infants required supplemental oxygen at 28 days’ postnatal age (14/18 vs 8/21, P < .05) and 36 weeks’ PMA (8/16 vs 5/20, P = .12).

Conclusion: In preterm infants at risk for chronic lung disease, a pulsed course of dexamethasone has fewer side effects than a long course but may be less effective at preventing chronic lung disease. (J Pediatr 1998;133:395-400)