Maternal and amniotic fluid steroids throughout human pregnancy

Area of Science:

• Reproductive endocrinology
• Prenatal diagnostics

Background:

• Steroid hormone profiling in pregnancy is crucial for understanding fetal development and identifying potential complications.
• Amniotic fluid and maternal serum provide distinct insights into the endocrine environment during gestation.

Purpose of the Study:

• To measure and compare concentrations of key androgens and progestins in amniotic fluid and maternal blood across gestation.
• To investigate potential sex-based differences in steroid levels during early pregnancy.
• To assess the utility of amniotic fluid steroid analysis in detecting specific fetal and placental conditions.

Main Methods:

• Radioimmunoassay (RIA) was employed to quantify testosterone, dihydrotestosterone, androstenedione, progesterone, 17 alpha-hydroxyprogesterone, and estradiol.
• Samples were collected from normal pregnancies between 14 and 40 weeks of gestation.
• Simultaneous measurements were performed in amniotic fluid and maternal peripheral blood.

Main Results:

• Significant sex differences in amniotic fluid androgen levels (testosterone, dihydrotestosterone, androstenedione) were observed before 20 weeks, with higher concentrations in male pregnancies.
• Elevated amniotic fluid 17 alpha-hydroxyprogesterone was noted in a fetus with congenital adrenal hyperplasia.
• Markedly increased steroid levels in amniotic fluid were found in a pregnancy with molar degeneration of the placenta.
• Maternal peripheral blood dihydrotestosterone also showed a sex difference before 20 weeks, higher in male pregnancies.
• No significant correlation was found between maternal serum and amniotic fluid steroid levels.

Conclusions:

• Amniotic fluid steroid hormone profiles, particularly androgens, exhibit sex-specific patterns in early to mid-gestation.
• Amniotic fluid steroid analysis holds potential for prenatal diagnosis of conditions like congenital adrenal hyperplasia and placental abnormalities.
• Maternal serum steroid levels do not reliably reflect the amniotic fluid steroid milieu during pregnancy.