Many women with 21-hydroxylase (21-OH)-deficient nonclassic adrenal hyperplasia (NCAH) carry at least one allele containing a severe mutation of CYP21, and as such are at risk for giving birth to an infant having classic adrenal hyperplasia (CAH). Infants with NCAH typically are asymptomatic at birth, in contrast to those with CAH, but they do develop symptoms of hyperandrogenism later in childhood or as adults. This international multicenter study, conducted both retrospectively and prospectively, was an attempt to determine how often mothers with 21-OH-deficient NCAH bear infants having CAH or NCAH. The 101 women entering the study had a total of 203 pregnancies that could be evaluated. Fourteen tertiary referral centers in nine countries participated in the study. The diagnosis of 21-OH-deficient NCAH was based on a baseline or post-ACTH level of 17-hydroxyprogesterone exceeding 10 ng/mL. Where feasible, the offspring underwent genotypic analysis.
Nearly half the women with NCAH presented with oligomenorrhea, and four had primary amenorrhea. More than two-thirds of pregnancies took place before the mother was diagnosed as having NCAH. Spontaneous miscarriages occurred in one-fourth of 138 pregnancies before NCAH was diagnosed but in only four of 65 pregnancies occurring after the diagnosis (6%). The incidence of CAH in 162 live births was 2.5%. Twenty-four children (15%) have been diagnosed as having NCAH. Five other female infants developed signs of hyperandrogenism but did not meet hormonal criteria for a diagnosis of NCAH. Three of the four live-born CAH children were White Jewish or Hispanic, as were two of three NCAH mothers giving birth to a CAH child.
In this international study, a woman with NCAH had a 2.5% chance of giving birth to a child having CAH and a 15% chance of having a child with NCAH. Preconception screening for 21-OH-deficient NCAH is especially important for hyperandrogenic or oligoovulatory women who wish to become pregnant. Glucocorticoid therapy before conception and/or before birth may favorably influence the outcome.