The effect of a single course of antenatal corticosteroids on maternal adrenal function at term

Objective: To determine if one course of antenatal corticosteroids at 32 weeks produces maternal adrenal suppression at term. Methods: The adrenocorticotropic hormone (ACTH) stimulation test was administered at 38 weeks to 11 pregnant women who had received a single course of antenatal betamethasone prior to 33 weeks and to six control subjects. Results: There was no difference in basal cortisol levels (mean ± standard deviation) between the two groups: 41.6 ± 6.9 μg/dl for controls versus 36.0 ± 7.8 μg/dl for the steroid group, p = 0.16. Peak cortisol levels at 45 min following ACTH stimulation were not different: 61.6 ± 3.5 μg/dl for controls versus 55.0 ± 2.6 μg/dl for the steroid group, p = 0.16. The power of the study to detect a statistical difference in the observed peak cortisol levels was greater than 95%. None of the study subjects had laboratory criteria or clinical signs of adrenal suppression. Conclusions: A single course of betamethasone for women at risk for preterm delivery does not produce adrenal insufficiency at term and stress dose steroids are not recommended.