title: Amniotic fluid testosterone and fetal sex determination in the first half of pregnancy.
abstract: The concentration of freely extractable testosterone in amniotic fluid was measured in 54 patients whose gestational ages ranged from 10 to 20 weeks; 31 of the fetuses were male and 23 were female. The mean amniotic fluid testosterone concentration was significantly higher with a male fetus than with a female fetus. On only 7 out of 31 occasions was the presence of a male fetus associated with amniotic fluid testosterone values below 100 pg/ml, whereas the values associated with a female fetus were never higher than 90 pg/ml. After 14 weeks gestation no amniotic fluid testosterone level was lower than 120 pg/ml in the presence of a male fetus.
mesh_terms: D000653:Amniotic Fluid / Q000032:analysis*; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D008297:Male; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012732:Sex Determination Analysis; D013739:Testosterone / Q000032:analysis*
chemical_list: D013739:Testosterone