Рathogenesis of the chronic placental insufficiency is largely determined by the type of diabetes mellitus and the degree of its compensation. Trophic function failure of placenta changes its hormonal activity, formation of respiratory disorders and development of oxidative stress. The histological structure of placentas among patients with type 1 diabetes mellitus (T1D) is represented by reduced chorionic villi dimensions of all levels. Stromal edema and increased number of mesenchymal stromal cells are found in the stem and intermediate villi, and hypervascularisation and thickening of syncytiocapillary membranes are detected in terminal villi. In type 2 diabetes mellitus (T2D), the histological structure of the placenta may be represented as a premature maturation and abnormal immaturity of the villous tree with focal fibrosis of villi stroma, hypervascularisation of villi, abundance of syncytial nodules and infarction in the subchorial space. The peculiarity of the placenta structure in gestational diabetes mellitus is predominantly an intermediate immature type of development with angiogenesis abnormality. Angiogenesis processes failure and endothelial dysfunction in chorionic villi associated with hyperglycaemia change the permeability of cell membranes, transferring cells to anaerobic respiration. Metabolic imbalance in the placenta causes the development of diabetic micro-angiopathy in the fetal-placental complex, antenatal hypoxia and negative perinatal outcomes
