Estrogen Formation and Its Transference in Placenta at Term

抄録

To clarify the transplacental passage of steroids at term, concentra-tions of steroids including free and conjugated estrone, estriol, and their precursors dehydroepiandrosterone (DHA) and 16αOH-DHA in the maternal vein (MV), uterine vein (Ut-V), retroplacental hematoma (RPH), umbilical artery (UA) and umbilical vein (UV) obtained at elective Cesarean section were measured. Gradients of steroid concentrations were analyzed. Significantly higher values of DHA and estrone in RPH were observed, which suggested that these steroids were secreted from the placenta to maternal circulation. Concen-trations of conjugated estriol, 16aOH-DHA, estrone and estriol in RPH were compatible with those in fetal circulation indicating the transplacental passage of those compounds from the fetus to the mother. Conjugated DHA concentration in RPH was lower than that in the umbilical cord blood. These results, with the finding of high DHA and estrone concentrations in RPH, suggest that conjugated DHA reaching to the placenta was mostly metabolized. The results indicate that transplacental passage from the fetus to the mother may depend on the steroids derived from the fetus.