Androgen profiles in full-term maternal-placental-fetal units

Although steroid metabolism in the maternal-placental-fetal unit is indispensable for pregnancy, the metabolic processes of each steroid are poorly understood. In the present study, we analyzed androgen profiles in 16 healthy full-term maternal-placental-fetal units. Classical and 11-oxygenated androgens in postnatal maternal blood, placental tissue, and cord blood were quantified using liquid chromatography-tandem mass spectrometry. We examined the effects of fetal sex and advanced maternal age (≥ 35 years) on steroid levels and analyzed correlations among steroid levels in paired samples. The results showed variation in steroid levels among samples. The placenta was enriched with 11-ketoandrostenedione (11KA4) and estradiol (E2). Maternal and cord blood samples contained large amounts of 11β-hydroxyandrostenedione (11OHA4). Steroid levels were comparable between male and female fetuses, except for high T levels in male cord blood samples, and between groups with and without advanced maternal age. 11OHA4 levels in maternal blood were correlated with 11KA4 levels in placental and cord blood samples. Classical androgen levels in the maternal blood were linked to E2 levels in the placenta. This study highlights inter-individual variations in steroid levels in healthy full-term maternal-placental-fetal units, which cannot be attributed to fetal sex or advanced maternal age. The placenta appears to be a unique steroidogenic organ characterized by high E2 and 11KA4 levels and low 11OHA4 levels. This study provides indirect evidence of close interaction across the maternal-placental-fetal unit for androgen metabolism. Given the small sample size and several methodological limitations, our results await further validation.