Hydrometrocolpos following prenatal dexamethasone treatment for congenital adrenal hyperplasia (21-hydroxylase deficiency).

A female with congenital adrenal hyperplasia (21-hydroxylase deficiency) received prenatal dexamethasone treatment. Suppression of the fetal adrenal was initially inadequate but adequate in later pregnancy. The baby showed masculinisation without clitoral enlargement and a narrow urogenital sinus with resulting hydrometrocolpos. It is possible that dexamethasone treatment which is initially inadequate increases the risk of this latter complication.