Amniotic fluid testosterone and follicle-stimulating hormone for fetal sex determination in the second trimester of pregnancy

Summary

The concentrations of testosterone and follic estimulating hormone (FSH) in amniotic fluid were determined in 110 pregnancies, from 11 to 22 weeks maturity. Fifty-eight of the fetuses were male and 52 were female. The two indices were compared for their value for fetal sex diagnosis in the second trimester.

Mean testosterone concentration was 3·5 times higher in the presence of a male fetus. After 13 weeks, fetal sex could be predicted in 38 of the 43 subjects with a male fetus and in 34 of the 38 subjects with a female fetus. After 13 weeks, mean FSH concentration was 4·6 times higher with a female than a male fetus. Fetal sex could be predicted with FSH in 19 of the 38 subjects with a female fetus. Determination of testosterone is a valuable index and should be carried cut in the first instance. FSH should be determined in cases where the testosterone level is equivocal. This permitted diagnosis in every instance