In patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, the concentrations of the cortisol precursor 17-α hydroxyprogesterone (17-OHP) and its metabolite Δ4-androstenedione (Δ4A) are increased. CAH was diagnosed in twins by measurement of 17-OHP and Δ4A concentrations in amniotic fluid obtained by amniocentesis from both amniotic cavities at 17 weeks' gestation. Both prenatal karyotypes were 46,XX. Spontaneous labor and delivery of 2 nonviable fetuses with genital masculinization occurred at 26 weeks' gestation. It is concluded that Δ4A measurement, like 17-OHP quantitation, is valuable in the prenatal diagnosis of CAH; that both methods appear useful in prediction of CAH in twin fetuses; and that abnormal adrenal-mediated masculinization in female CAH is well established before the end of the second trimester.
© 1980 The American College of Obstetricians and Gynecologists