Evaluation of Estetrol Metabolism in the Fetoplacental Unit after DHAS Administration to Pregnant Women Near Term

To assess the significance of measurement of plasma estetrol after dehydro-epiandrosterone sulfate (DHAS), 100 mg of DHAS was injected 30–60 minutes (7 cases), 120 minutes (6 cases), 180 - 240 minutes (5 cases) before delivery into 18 normal obstetric patients (37–39w) undergoing elective repeat cesarean section. At delivery, maternal peripheral vein (MV), umbilical vein (UV), and umbilical artery (UA) blood and amniotic fluid (AF) were obtained, and unconjugated estetrol in each compartment was measured. A significant increase of plasma estetrol concentration was observed in MV, UV, and UA, with the maximal levels at 180–240 minutes, but not in AF. The increase of plasma estetrol concentrations were higher in UV and UA than in MV. However, no significant difference in the plasma estetrol concentration was seen between UV and UA after DHAS injection. A significant correlation was found between individual MV and UV plasma estetrol concentrations after DHAS injection. The data indicate that determination of a maternal plasma estetrol rise after DHAS injection reflects fetoplacental function and may provide further useful information to evaluate fetal well being.