Drug of choice for prenatal treatment of CAH due to 21 alpha hydroxylase deficiency:

Recommendations for pregnancies at risk , consist of administration of Dexamethasone, Dexamethasone Steroid that readily crosses the placenta, in an amount of 20ug/kg pre-pregnancy maternal weight daily. This suppresses secretion of steroids by the fetal adrenal, including secretion of adrenal androgens. If staed by 6 week of gestation, it reduces virilization of the external genitals in affected females. Chorionic villus biopsy is then performed to determine the sex and genotype of the fetus; therapy is continued only if the fetus is an affected female. DNA analysis of fetal cells isolated from maternal plasma for sex determination and CYP21 gene analysis may permit earlier identification of the affected female fetus.