In contrast to subfertility often reported in women suffering from the classical form of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, fertility in nonclassical CAH (NC-CAH) has been rarely studied. Our objective was to evaluate fertility in NC-CAH women.

We studied 190 NC-CAH women (161 probands + 29 first degree relatives). Only 20 probands had consulted for infertility (12%), either alone or associated with hirsutism or menstrual cycle disorders. The diagnosis was established on post-ACTH 17-hydroxyprogesterone 10 ng/ml or greater and further characterized by CYP21A2 gene analysis.

Ninety-five of the 190 women wanted pregnancy (aged 26.7 +/- 8.9 yr); 187 pregnancies occurred in 85 women, which resulted in 141 births in 82 of them. Ninety-nine pregnancies (52.9%) occurred before the diagnosis of NC-CAH (96 spontaneously and three with ovulation inducers) whereas 98 occurred after diagnosis (11 spontaneously and 77 with hydrocortisone treatment); 83% of pregnancies were obtained within 1 yr. The rate of miscarriages was 6.5% for pregnancies obtained with glucocorticoid treatment vs. 26.3% without. Two of the 141 infants (1.5%) were born with classical CAH.

Subfertility is mild in NC-CAH. However, the rate of miscarriages is lower in pregnancies occurring with glucocorticoid treatment and argues for treating NC-CAH women wanting pregnancy. In addition, considering the high rate of heterozygotes for CYP21A2 mutations in the general population, it is essential to genotype the partner of patients with a severe mutation to predict the risk of classical CAH and offer genetic counseling.