Abstract: It was found that immunologic factors are the cause of 50% happening of idiopathic recurrent miscarriage. It is proved that progesterone plays an important role in the establishment of adequate immune environment in the early stages of pregnancy. The results of the study described in this article, as well as a number of other studies suggest that the use of such progesterone isomers as dydrogesterone in women with idiopathic recurrent pregnancy loss improves pregnancy outcomes - reduces the incidence of recurrent abortions, extends gestational age and reduces the risk of obstetric complications