Prevention of ambiguous genitalia by prenatal treatment with dexamethasone in pregnancies at risk for congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) refers to a family of monogenic inherited disorders of adrenal steroidogenesis most often caused by a deficiency of the 21-hydroxylase enzyme. In the classic forms of CAH (simple virilizing and salt-wasting), androgen excess causes external genital ambiguity in newborn females and progressive postnatal virilization in males and females. Prenatal treatment of CAH with dexamethasone has been successfully utilized for over a decade. This article reports on 595 pregnancies prenatally diagnosed using amniocentesis or chorionic villus sampling between 1978 and 2002 at the New York Presbyterian Hospital-Weill Medical College of Cornell University. No significant or enduring side effects were noted in the fetuses, indicating that dexamethasone treatment is safe. Prenatally treated newborns did not differ in weight from untreated, unaffected newborns. Based on our experience, prenatal diagnosis and treatment of 21-hydroxylase deficiency is effective in significantly reducing or eliminating virilization in the newborn female. Prevention of genital virilization in female newborns with classic CAH avoids the risk of sex misassignment and diminishes the need for corrective surgery and the resulting psychological impact that may extend into adulthood.