Objective: 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.
Study design: 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.
Results: 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.
Conclusion: Multiple weekly treatment cycles of betamethasone for fetal lung maturity administered between 24 and 34 weeks' gestation do not appear to cause adrenal suppression.