Betamethasone dosing interval: 12 or 24 hours apart? A randomized, noninferiority open trial.

Objective: We sought to determine whether the incidence of neonatal respiratory distress syndrome (RDS) is similar with 12- vs 24-hour dosing interval of betamethasone.

Study Design: This was a prospective, randomized, open, noninferiority trial. Mothers (n = 228) with a singleton or multiple pregnancies (fetuses = 260), between gestational age of 23-34 weeks, at risk for preterm delivery, received standard 2 doses of betamethasone either 12 or 24 hours apart in 2:1 ratio, respectively.

Results: Incidence of RDS was similar in the 2 cohorts (36.5% vs 37.3%; P = not significant). Women unable to receive the complete course of corticosteroids with the 24-hour interval can be reduced by half with the 12-hour interval. However, increased incidence of necrotizing enterocolitis was seen with 12-hour dosing (6.2% vs 0%; P = .03).

Conclusion: The 12-hour dosing interval is equivalent to the 24-hour dosing interval for prevention of RDS in neonates of mothers delivering prematurely. A larger multicenter study is needed to confirm our findings.