Clinical, anthropometric, and endocrine data were examined in 22 corticosteroid-treated, prenatally virilized women with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency and in 22 matched healthy controls. In view of the androgen excess, limited growth, and subfertility associated with CAH, the investigation focused on androgenic/anabolic status and circulating progesterone levels. CAH patients were shorter and had a significantly higher body mass index than the controls. One pregnancy was reported in the CAH group compared to 15 in the controls. Five of the CAH patients were judged as undersubstituted based on greatly elevated circulating levels of 17 alpha-hydroxyprogesterone. These five patients had elevated serum levels of progesterone (P) and testosterone (T) and elevated ratios between T and sex hormone-binding globulin, but subnormal levels of dehydroepiandrosterone (DHA) and its sulfate. The remaining 17 well substituted patients had elevated follicular phase levels of P, but subnormal levels of all androgens (4-androstene-3,17-dione, T, DHA, and DHA sulfate) and subnormal T/sex hormone-binding globulin ratios. Contrary to the apprehension that normally guides the treatment of CAH, well substituted patients may be considered hypoandrogenic rather than hyperandrogenic. The elevated levels of P may have a minipill-like effect, which may be one of the causes of the differences in fertility between salt-wasting and simple virilizing CAH.