Utero-placental bed is the cumulation of gestationally altered endometrium at the place of ovum attachment to the uterine wall. The key mechanism of this process is the cytotrophoblastic invasion. During iron deficiency anemia, an increase in the specific volume of the extravascular invasive trophoblast is taking place. Concern for the protein oxidative modification in iron deficiency anemia is due to the fact that in conditions of hypoxia, free radical processes in the blood and tissues are enhanced, and iron deficiency is additionally able to modify this problem. The purpose of the study was to establish the histochemical features of the processes of protein oxidative modification in the fractions of extravillous cytotrophoblast of the utero-placental bed depending on the degree of iron deficiency anemia in pregnant women. Material and methods. Quantitative characteristics of protein oxidative modification in the extravillous trophoblast of the utero-placental bed of pregnant women with iron deficiency anemia by means of the histochemical method using reactions with Bromophenol Blue on “acidic” and “basic” proteins according to Mikel Calvo method and computer microdensitometry. We studied 74 biopsies of the utero-placental bed of pregnant women with iron deficiency anemia of I, II and III degrees. The term of gestation was 37-40 weeks. Results and discussion. During physiological pregnancy, the ratio between "acidic" and "basic" proteins in trophoblast cells, even normally, is characterized by a predominance of "acidic" proteins, and evenly in both intravascular and extravascular fractions of cytotrophoblast. Intensification of processes of protein oxidative modification in the cytotrophoblast of the utero-placental bed during iron deficiency anemia of I-II degrees can be assessed as moderate, with an increase in the cells of the endothelium-replacing fraction of cytotrophoblast compared with the interstitial. In conditions of anemia of III degree, a significant predominance of "acidic" proteins in the intravascular cytotrophoblast was noted. Conclusion. During the physiological pregnancy, the intensity of protein oxidative modification was equal in all fractions of the extravillous cytotrophoblast in the utero-placental bed. In the case of gestation with iron deficiency anemia, significant intensification of the protein oxidative modification in the extravillous cytotrophoblast correlated with the severity of anemia. Background iron deficiency anemia significantly affected the processes of protein oxidative modification in the endothelium-replacing cytotrophoblast