Multiple courses of betamethasone to enhance fetal lung maturation do not suppress neonatal adrenal response.

Abstract

Our purpose was to evaluate the neonatal adrenal gland by provocative testing in neonates of mothers who had received multiple courses of betamethasone to enhance fetal lung maturity. Infants of mothers who had received >/=3 courses of betamethasone for fetal lung maturation were enrolled in the study. Twenty-four hours after delivery a baseline serum cortisol concentration was obtained. A synthetic adrenocorticotropic hormone (Cortrosyn) was administered (0.25 mg/1.73 m2). Two hours later a second serum cortisol concentration was obtained. An increase in serum cortisol in response to Cortrosyn was considered a positive test result. Nominal data were compared by means of the Student t test. There were 9 infants enrolled in the study. The mean number of betamethasone treatment cycles was 4.8 +/- 1.09. The mean baseline cortisol level was 2.23 +/- 0.52 microgram/dL, and the mean post-adrenocorticotropic hormone cortisol level was 9.86 +/- 1.70 microgram/dL. All neonates had a positive adrenocorticotropic hormone test result. Stepwise linear regression showed no association between the number of courses of betamethasone treatment cycles and the post-adrenocorticotropic hormone cortisol concentration. Multiple weekly treatment cycles of betamethasone for fetal lung maturity administered between 24 and 34 weeks' gestation do not appear to cause adrenal suppression.