Introduction. Investigation of the regulation processes concerning the number of cells is essential to specify the mechanisms of preterm maturation of the chorionic placental tree and preterm labor, that was first carried out for the first time in case of iron deficiency anemia of pregnancy.Objective: on the basis of immunohistochemical examination to find quantitative parameters of the cellular proliferation processes and apoptosis in the villous trophoblast in case of iron deficiency anemia of pregnancy and preterm maturation of the placental chorionic tree.Material and methods. 182 placentas were examined. The design of the study assumed distribution of the two main groups and three groups of comparison. Optic density of immunohistochemical staining and the antigens Bcl‑2 and BAX were measured by means of computer microdensitometric method. The number of Ki‑67‑positive nuclei was calculated in per mille.Results. Immunohistochemical staining on the antigens Всl‑2 and ВAX was determined in the cytoplasm of the chorionic placental villous trophoblast, and on the antigen Ki‑67 in the nuclei of the placental chorionic villous trophoblast. Differences in the average tendencies concerning every examined antigen were determined which was reflected in the conclusions of the article.Conclusions. Iron deficiency anemia of pregnancy and preterm maturation of the chorionic tree both separately and in their combination result in intensification of proliferation processes in the placental chorionic villous trophoblast. Association of iron deficiency anemia of pregnancy and preterm maturation of the chorionic tree results in decrease of the concentration of anti-apoptotic protein Всl‑2 in the cytoplasm of the chorionic villous trophoblast. ВAX-dependent apoptosis in the trophoblast of the placental chorionic villi increases both in case of iron deficiency anemia of pregnancy and preterm maturation of the placental chorionic villi, and in case of their combination this process becomes maximally pronounced.