Hypospadias, androgen biosynthesis, and synthetic progestogens during pregnancy.

Treatment of pregnant rats from days 13 through 19 with a synthetic steroid known to inhibit 3 beta-hydroxysteroid oxidoreductase was associated with a significant reduction in the capacity of fetal Wolffian ducts to metabolize dehydroepiandrosterone. In contrast, similar treatment with norethisterone acetate, alone or in combination with ethynylestradiol, or medroxyprogesterone acetate, at up to 100 times the human dose, was without effect on metabolism of dehydroepiandrosterone. It is suggested that the use of synthetic progestogens during pregnancy is unlikely to increase the risk of hypospadias due to inhibition of testosterone biosynthesis.