[Determination of steroid hormones in the amniotic fluid in prenatal genetic diagnosis].

In amniotic fluid from the second trimester of pregnancy levels of total and free testosterone, 17 alpha-hydroxyprogesterone and dehydroepiandrosterone were assessed. The median levels of total testosterone during the 15th to 24th week are 0.82 +/- 0.31 nmol/l in pregnancies with male foetuses and 0.32 +/- 0.11 nmol/l in pregnancies with female foetuses. The levels of free testosterone assessed by calculation from concentrations of SHBG and total testosterone are 0.15 +/- 0.04 for male and 0.05 +/- 0.04 nmol/l for female foetuses. The diagnostic reliability of sex determination of the foetus from the total testosterone concentration in amniotic fluid is 94% and estimation of free testosterone increases it further. The median normal 17 alpha-hydroxyprogesterone levels during the 15th to 23rd week of pregnancy are 8.7 +/- 3.5 nmol/l and do not depend on the sex of the foetus and week of pregnancy. The levels of dehydroepiandrosterone in amniotic fluid from the second trimester of pregnancy are in male foetuses 0.64 +/- 0.33 nmol/l and 0.61 +/- 0.32 nmol/l in female foetuses and do not differ. Assessment of testosterone levels serves as a supplementary method for determination of the sex of the foetus and may play an important part in the prenatal diagnosis of syndromes with agenesis of testicles. Estimation of 17 alpha-hydroxyprogesterone is used in prenatal diagnosis of congenital adrenal hyperplasia, estimation of dehydroepiandrosterone can be used in the prenatal diagnosis of hereditary forms of adrenal hypofunction.