Congenital adrenal hyperplasia due to 21-hydroxylase deficiency suspected in 14 newborns (5 F, 9 M), was treated prenatally with dexamethasone from weeks 7-9 of gestation. The 24 h urinary excretion of selected adrenocortical steroids derived from fetal and definitive adrenal zones was evaluated in these newborns at the age of 3 9 days. Among 11 babies born healthy, in one of six treated until confirmation of male karyotype in gestational weeks 12-17 and in four of five treated until delivery, suppression of fetal adrenal zone steroids was observed, accompanied additionally in three by a diminished excretion of tetrahydrocortisone. In three babies born affected (2 male, 1 female), excretion of 17alpha-hydroxyprogesterone and 21-deoxycortisol metabolites did not differ from 12 affected, age-matched controls, not treated prenatally. However, some influence on suppression of the fetal adrenal zone metabolite 16alpha-hydroxypregnenolone was observed in two newborns treated until delivery.
Conclusions: Heterogeneity in the fetal adrenal response to maternal dexamethasone treatment was confirmed. Suppression of fetal adrenals, especially within the fetal adrenal zone, can be observed in some babies born healthy until at least 1 week after birth.