Abstract
The relationship between corpus luteum progesterone and rate of abortion is well known. Measurements of progesterone and clinical observations can demonstrate that low serum progesterone levels indicate, even better than human chorionic gonadotropin (hCG) measurements ,an abnormal course of pregnancy. Early substitution seems to be the decisive therapeutic step. In relation to the concentration at the fetomaternal interphase progesterone leads to direct and indirect suppression of T-cell reactions. Progesterone acts synergistically with prostaglandin E2 immunosuppressive. Interleukin-2-induced cellular cytotoxicity is suppressed. Progesterone induces a number of proteins such as PP14 ,which inhibit the activity of T-cells and natural killer cells. Mitogenic lymphocyte reactivity is lowered. To date ,results of immunological therapies do not prove the effectiveness of immunological treatment modalities.