[Testosterone-estradiol binding globulin and sex steroids during pregnancy and at delivery]

Testosterone-estradiol binding globulin (TeBG), testosterone, estradiol-17 beta, index-T (testosterone not bound to TeBG) and index-E2 were determined during pregnancy, at parturition, in the umbilical artery and vein, and during postpartum periods. TeBG showed a rapid increase during the early pregnancy and then it reached a certain level at the mid pregnancy. At parturition, it decreased to about half of the late pregnancy. In the umbilical artery and vein the level was extremely low. Testosterone gradually increased from the early to the late pregnancy. However, index-T reached its lowest level during the 5th month of pregnancy. In the umbilical artery and vein testosterone exhibited a slightly lower level in comparison with the maternal blood but in contrast to this index-T exhibited five times higher level in the umbilical artery and vein than in the maternal blood. Estradiol-17 beta exhibited a linear increase from the early to the late pregnancy but index-E2 showed a sudden increase during the late pregnancy. The levels in the maternal blood at the parturition and in the umbilical artery and vein were compared: The estradiol-17 beta levels were maternal blood greater than umbilical vein greater than umbilical artery and the index-E2 levels were maternal blood .=. umbilical vein greater than umbilical artery.