Objective — to determine the quantitative characteristics of blood circulation in the fetal venous duct in pregnancy complicated by preeclampsia, and in its progression. Material and methods. During the 11—14, 18—21, and 30—34-week gestational periods, 72 patients with moderate preeclampsia-complicated pregnancies (the main group) and 60 patients with normal pregnancy progression and childbirth (the control group) were examined. The standard obstetric and clinical-laboratory studies were performed; the study of chorionic biochemical function with determination of the content of serum markers of pregnancy-associated plasma protein-A (PAPP-A), β-subunit of human chorionic gonadotropin, placental α-microglobulin-1 (PAMG-1), and visual echographic and dopplerometric study of fetal hemodynamics. Results. Disruption of blood flow into the intravascular space along the spiral arteries and difficulty in venous outflow from the intravascular space during pregnancy complicated by preeclampsia lead to changes in the spectrum and quantitative characteristics of fetal venous circulation, which consisted of an increase in venous resistance and, consequently, a reduction of the rate of blood flow in the fetal venous duct and an increase in the angle-independent parameters. Increased vascular resistance in the fetal venous duct may indicate a reduced blood flow in the fetal venous channel, which leads to progressive hypovolemia of the fetus, clinically recognized as the development of preeclampsia by such manifestations of placental insufficiency as intrauterine hypoxia, fetal growth retardation and ischemic-hypoxic lesions of the newborn. Conclusion. The study of blood flow in the fetal venous duct can be used not only for comprehensive diagnosis of fetal malformations, but also for predicting serious disorders in the fetal condition.