Prenatal Sex Determination by Amniocentesis

By studying amniotic fluid obtained during different stages of pregnancy, the authors were able to draw conclusions concerning the sex of the fetus from the sex chromatin content of amniotic cells. Amniotic fluid was obtained transvaginally from 100 women during early pregnancy, transabdominally from 10 during the third trimester, and by transcervieal amniocentesis from 10 parturients. The number of cells that could be analyzed increased with advancing pregnancy, showing sex chromatin positivity up to 4% in male, and between 12 and 26% in female fetuses. Amniotic cells suitable for analysis were not found before the twelfth week of pregnancy. For such prenatal sex determinations, transvaginal amniocentesis between the fourteenth and sixteenth weeks of gestation, is recommended. This method is considered to be suitable for prenatal selection of persons doomed to have sex-linked hereditary disease. When the sex chromatin count is 4 to 12%, analysis of the chromosome content by culture may be significant.