Amniotic fluid testosterone and follicle stimulating hormone levels as indicators of fetal sex during mid-pregnancy.

Abstract

AbstractMidtrimester (14–22 weeks of gestation) amniotic fluid hormone levels were measured as indicators of fetal sex in 99 pregnancies (66 with a male fetus and 33 with a female fetus). Statistically significant didfferences in testosterone (T), androstenedione (A), and follicle stimulating hormone (FSH) levels were observed between pregnancies with fetuses of differing sex. No significant difference was observed for estrone (E1), estradiol (E2), or progesterone (P) levels.Fetal sex was accurately predicted in 96 of 99 pregnancies using a criterion of T ≥ 100 pg/ml for males and in 94 of 99 pregnancies using a criterion of FSH ≥ 3 mIU/ml for females. In the 3 cases in which the fetus was male but the T level was < 100 pg/ml, the FSH was clearly in the male range. Likewise, in 5 cases in which the fetal sex was not correctly predicted by the FSH level, the T level confirmed the karyotype.It is proposed that measurement of amniotic fluid testosterone levels would be of value in detecting errors in prenatal cytogenetic diagnosis when there is incorrect fetal sexing. It is suggested that FSH determinations be performed when the amniotic fluid testosterone does not confirm the karyotype, and that when there is a discrepancy between the karyotype and both of these measurements, repeat amniocentesis should be considered.