Antenatal diagnosis of congenital adrenal hyperplasia.

The concentration of 17-OH-progesterone (17-OHP) was measured retrospectively in a second-trimester amniotic-fluid sample obtained from a mother who had an infant with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. The concentration was more than three times the mean amniotic-fluid-17OHP concentration determined in pregnancies of comparable gestational age with normal outcome. In four further pregnancies tested, where the parents were heterozygous for CAH, amniotic-fluid concentrations of 17-OHP were normal. To date, three of the mothers have delivered normal infants. CAH can be detected in early pregnancy by specific radioimmunoassay techniques for steroid-hormone analysis in amniotic fluid. This antenatal test could be useful in those cases in which parents do not wish to risk having affected offspring.