[Dynamics of estriol-16-glucosiduronate (E3-16-G) in early pregnancy -- its prognostic value in complicated pregnancy (author's transl)].

Urinary estriol-16-glucosiduronate (E3-16-G) in early pregnancy was measured by a direct radioimmunoassay which was highly specific for the compound and did not require hydrolysis or chromatography. The level of E3-16-G in normal pregnant women increased as pregnancy progressed and was over the level in non-pregnant women after 6 weeks gestation. The levels were lower in complicated pregnancies, namely threatened abortion, intra uterine fetal death, ectopic pregnancy, anencephalus and so on. Decreases of urinary E3-16-G in threatened abortion were more rapid than those of urinary hCG, which was used as a useful prognostic indicator in those cases. These results suggested the possibility that the fetus played some role in the production of E3-16-G in early pregnancy. In order to clarify the role of the fetus in the formation of E3-16-G, it was measured in the maternal peripheral vein, uterine artery and vein, and in the fetal tissue at hysterectomy in complicated pregnancies (three cases). These results also suggested the possibility that E3-16-G was produced by the fetus. In the in vitro experiments where 14C-E3 was incubated with various tissues in early pregnancy, it was demonstrated that 14C-E3 was conjugated to be E3-16-G by homogenate of the fetal tissue in 8 weeks gestation, and by the liver and by the kidney in 13 weeks gestation but not by chorionic tissue. These results indicated that the conjugation process of E3, though perhaps not entirely, proceeds in the fetus and the urinary determination of E3-16-G might give us good information about the fetus in pregnant women.