Amniotic fluid testosterone and follicle-stimulating hormone assay in the prenatal determination of fetal sex.
Amniotic fluid testosterone was assayed by radioimmunoassay in 812 samples taken at 16 weeks' gestation at the time of genetic amniocentesis. In each of 361 samples (45% of total), correct assignment of fetal sex was made where the testosterone level was above 33.8 ng/ml for male fetuses and below 16.2 ng/ml for female fetuses. In each of 159 of 353 (45%) samples assayed for follicle-stimulating hormone (FSH), levels were below 7.6 mlU/ml for male fetuses and above 10.9 mlU/ml for female fetuses. By combining the two assays in the testosterone/FSH ratio, correct assignment of sex was made in each of 282 samples (80%). The percentage of samples in which correct assignment was achieved was greater for female fetuses (ratio less than 2.2 in 161/187 [86%]) than for male fetuses (ratio greater than 3.4 in 121/166 [72%]). The testosterone/FSH ratio holds promise as a rapid biochemical screening tool in the prenatal diagnosis of fetal sex in X-linked disorders.
D000649:Amniocentesis; D000653:Amniotic Fluid / Q000032:analysis*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000032:analysis*; D006801:Humans; D011247:Pregnancy; D012732:Sex Determination Analysis; D013739:Testosterone / Q000032:analysis*
D013739:Testosterone; D005640:Follicle Stimulating Hormone