High risk pregnancies should be staed of Dexamathasone, that readily crosses placenta, in an amount of 20 mu/kg in 2-3 divided doses. This surpasses secretion of steroids by fetal adrenals, including secretion of fetal adrenal androgens. If staed 6 weeks of gestation, it ameliorates virilization of external genitals in affected female fetus. Ref: Kligman, Behrman, Jenson, Stanton (2008), Chapter 577, "Congenital Adrenal Hyperplasia", In the book, "Nelson's Textbook of Pediatrics", Volume 2, 18th Edition, New Delhi, Page 2364