[The structural characteristics of the placental barrier during the dynamics of pregnancy in women over 35].

Biopsy of chorion early in the course of pregnancy is of great diagnostic value. Morphological, electron microscopic, and morphometric findings for the shaggy chorion during the I to II trimesters of pregnancy show that in women aged 35 to 45 years with physiological pregnancy changes occur in all structures of the placental barrier as compared to young women. During the I and II trimesters of pregnancy, those women who range from 35 to 45 years old exhibit disturbances in the processes of chorion vascularization, with the compensatory and adaptive reactions developing on the cellular and subcellular levels. In women aged 41 to 45 years, disordered processes of vascularization in the placental barrier are recordable together with dystrophic changes in the syncytiotrophoblast and compensatory and adaptive reactions in endothelial cells of fetal capillaries.