[Interaction of placental hormones in mother-embryo system (author's transl)].

Described in this paper is the relationship between chorionic gonadotrophin, placental lactogen, progesterone, oestradiol and oestriol in the blood of mother and embryo. The concentrations of human chorionic gonadotrophin (HCG) and human placental lactogen (HPL) in the mother's blood toward the full term of pregnancy were found to be between 300 and 800 times as high as those in foetal blood. No arteriovenous difference in concentration between the same hormones was recorded from the vessels of the umbilical cord. While the concentrations of progesterone, unconjugated oestriol, and total oestriol in the mother's blood were lower than those in foetal blood, the opposite was true for oestradiol which was lower in foetal blood. Clearly reduced levels of progesterone, unconjugated oestriol, and oestradiol but increased levels of total oestriol were recorded from the umbilical artery, as compared to the umbilical vein. The above findings are intended to encourage thinking about selective penetrability of the placenta, whenever hormone preparations are prescribed in advanced pregnancy.