<prompt> Which drugs are used for prenatal therapy of congenital adrenal hyperplasia?HydrocoisonePrednisoloneFludrocoisoneDexamethasone  <response>: High risk pregnancies should be staed of Dexamathasone, that readily crosses placenta, in an amount of 20 mukg 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, Nelsons Textbook of Pediatrics, Volume 2, 18th Edition, New Delhi, Page 2364 