Uterine and peripheral blood concentrations of human chorionic gonadotropin and human placental lactogen

One hypothesis is that two placental protein hormones (human placental lactogen and human chorionic gonadotropin) are effective immunosuppressive agents that prevents the rejection of a fetus because of their very high concentrations. In patients undergoing elective repeat cesarean sections at term, we measured the concentrations of these hormones in blood obtained simultaneously from draining ovarian veins and peripheral veins, and found no significant differences.