Hypothalamic-pituitary-adrenal axis function in premature neonates after extensive prenatal treatment with...

Tests of hypothalamic-pituitary-adrenal axis function were performed on a set of 32-weeks' gestation triplets whose mother received 16 injections of betamethasone over 8 weeks prior to delivery to induce fetal lung maturation. The purpose of these studies was to determine if clinically significant suppression of fetal adrenocortical function occurred as a result of this repeated and prolonged prenatal exposure to glucocorticoids. Serum cortisol levels were measured on cord blood from each patient. Morning serum cortisol and 11-deoxycortisol levels were measured before and after an oral dose of metyrapone given at midnight on day 5. All three infants were clinically well at birth and had no evidence of hyaline membrane disease. Cord blood cortisol levels were low in each infant (1.97 +/- 0.25 micrograms/dl). By day 5, morning cortisol levels had become normal for each infant (10.77 +/- 2.42 micrograms/dl). Following the metyrapone dose, the 11-deoxycortisol levels rose 10- to 20-fold for each infant, indicating normal function of the hypothalamic-pituitary-adrenal axis by day 6. Adrenocortical suppression following multiple courses of prenatal betamethasone appears to be similar in degree and duration to that reported following brief antenatal therapy with this medication. Further studies are needed to confirm these anecdotal observations.