The investigation was undertaken to study the specific features of the immune status and hormonal background in pregnant women with a history of recurrent miscarriage (RM) (3 or more consecutive spontaneous miscarriages before the current pregnancy). A study group consisted of 10 pregnant women with a history of RM; a control group included 11 pregnant women with physiological pregnancy. The surface phenotype of peripheral blood lymphocytes was assessed by the flow cytometric immunofluorescence assay; serum hormone concentrations were determined by an immunochemical method. There was a reduction in CD3+ T lymphocytes and an increase in the proportion of CD3-CD16+CD56+NK cells in peripheral blood in RM. The lymphocytes had signs of activation detected from the higher expression of the marker HLA-DR. The endocrine status of the women with RM was characterized by the increased serum concentrations of progesterone and α-fetoprotein. A high negative correlation was found between the serum concentration of human chorionic gonadotropin and the expression of lymphocyte activation markers in the peripheral blood of pregnant women with a history of RM, but it was absent in those with physiological pregnancy. It was suggested that human chorionic gonadotropin might be involved in the induction and maintenance of immunological tolerance to the fetus in pregnant women with impaired reproductive function.