Introduction: Study of features of renal function, some indicators homeostasis in women with mild preeclampsia. We have studied 50 women with physiological pregnancy, 100 pregnant women with mild PE (II group) in gestational age 30-34 weeks. The results of the data, it should be emphasized that among the numerous violations of various functions of the body of pregnant women with mild preeclampsia. The most prominent is hypovolemia due to preferential reduction of plasma volume, hypoproteinemia due to proteinuria and reduced renal perfusion parameters with the deterioration of their functional capacity. Objective: The study of the features of the functional state of the kidneys, some indicators of homeostasis in women during pregnancy complicated by preeclampsia. Method: We studied 50 women with physiological pregnancy, 100 pregnant women with mild PE (group I), 50 pregnant women with severe PE (group II) at a gestational age of 30-34 weeks. Clinical and laboratory studies were used, including general analysis of blood and urine, fibrinogen, time blood according to Sukharev, a study of the amount of protein in the blood, counting the amount of protein in daily urine and functional methods for assessing the condition of pregnant women. Result: Assessing the results obtained, it can be indicated that pregnant women with severe preeclampsia have a greater tendency to hypernatremia than pregnant women with mild preeclampsia, which significantly exceeds the concentration of sodium in the plasma of healthy pregnant women. Changes from other electrolytes are not significant. Conclusion: All this indicates that such a contingent of pregnant women poses a great danger in terms of the occurrence of various complications during pregnancy, childbirth and the postpartum period.