title: Amniotic fluid testosterone and follicle-stimulating hormone assay in the prenatal determination of fetal sex.
abstract: 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.
mesh_terms: 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*
chemical_list: D013739:Testosterone; D005640:Follicle Stimulating Hormone