The aim of the research was to study some indices of morphofunctional state of lymphocytes in the peripheral blood under a complicated course of pregnancy in women of Khabarovsk. 96 women were examined in different trimesters of gestation. Two main groups depending on the type of complications were formed: the first group consisted of pregnant women with vaginitis, the second group had women whose pregnancy was complicated with clinical manifestations in the form of edemas, proteinuria and hypertensive disorders. The group of comparison included the women without complications. In the peripheral blood of the women under study with the method of high tech automated digital system of blood smear test VISION HEMA there was done a morphometric assessment of lymphocytes and with histochemical methods there was found a level of fermentation activity of succinate dehydrogenase (SDH), α-glycerophosphate dehydrogenase (α-GPDH) and lactate dehydrogenase (LDH). By morphometric studies of lymphocytes of the peripheral blood in pregnant women of the first group in the III trimester of gestation the indices of the square of the cell, of cytoplasm, cytoplasm brightness, the square of the nucleus and the brightness of the nucleus were 102.33±9.83 mсm², 36.84±4.88 mсm², 181.39±6.94 units of optical density, 65.69±6.87 mсm², 97.44±6.88 units of optical density, respectively (in the group of the comparison these data were 121.31±4.44 mсm²; 46.14±2.52 mсm²; 167.74±3.44 units of optical density; 75.33±2.66 mkm², 88.00±3.36 units of optical density, respectively). In the second group of women the same data in the same period of pregnancy corresponded to the following values: 128.44±4.89 mсm², 57.15±3.87 mсm², 173.53±4.65 units of optical density, 70.95±3.39 mсm² and 91.13±4.93 units of optical density (in the group of comparison there were the following data: 109.92±3.57 mсm², 39.63±1.53 mсm², 158.96±2.63 units of optical density, 75.37±3.23 mсm², 82.16±2.58 units of optical density, respectively). By the results of histochemical studies the level of activity of enzymes SDH, α-GPDH, LDH in the first group of pregnancy was 15.38±2.10, 10.72±0.58 and 20.53±2.36 pellet/cell, respectively. And just the other way round in pregnant women of the second group there was revealed a statistically reliable suppression of fermentation activity of these enzymes: 9.11±0.75 (p<0.05); 9.61±1.06 (p>0.05); 8.31±1.20 (p<0.05) pellet/cell in regard to the data in the group of comparison (12.84±1.21; 12.18±1.13 and 13.09±0.78 pellet/cell, respectively). Thus the changes of morphometric indices characterizing parameters of the cell, the nucleus and lymphocytes cytoplasm in a complex study with their fermentation activity can be extra diagnostic criteria of the formation of different complications during pregnancy. The obtained data allow to justify in-time application of medications for the correction of metabolic disorders of immune competent cells with the aim to decrease unfavorable perinatal outcomes.