Pregnant women are the most sensitive contingent to the effects of the virus and this is due to adaptive physiological changes in the woman’s bronchopulmonary system and features of the immune system. “Physiological tolerance” is formed during pregnancy and this is accompanied by a decrease in the level of T-helpers and natural killers in pregnant women and leads to a decrease in the resistance of the woman’s body to the action of altering viral and bacterial agents. Purpose - to reveal the peculiarities and clarify the nature of clinical and instrumental changes in pregnant women with a severe course of COVID-19 under dynamic observation. Materials and methods. The study included 40 pregnant women with coronavirus disease with a gestational age of 22 to 41 weeks, who formed the main group. The control group consisted of 40 women whose pregnancies were not complicated by coronavirus disease. The course of the disease and the influence of the coronavirus infection on the course of pregnancy were evaluated according to the results of: general - clinical examination, laboratory examination (general blood test, biochemical blood test, coagulogram, C-reactive protein, D-dimer, procalcitonin and interleukin 6), instrumental examination (cardiotocographic research, pulse oximetry). Results. Peculiarities of changes in clinical and laboratory indicators in pregnant women were studied depending on the stage of development of the coronavirus disease. During the study, it was established: a significant increase in the level of indicators in accordance with the control group, namely an increase in leukocytes by 38.2% to 10.07±1.59×109/l (р<0.05), an increase in thrombocytes by 35% to 314.36±49.70 (р<0.05), an increase in monocytes by 22.5% to 7.08±1.12 and a decrease in lymphocytes to 13.46±2.13, which is 51.2% lower than the indicators of the control group. The level of C-reactive protein in pregnant women with COVID-19 is probably higher than in all groups of examined patients. The level of D-dimer exceeded the indicators of the control group in patients of all groups with the maximum values of indicators in patients at the time of admission to department of anaesthesiology and intense therapy (DAIT) and was 4867.42 ng FEU/ml, which was 6.3 times higher than the level of the control group (p<0.05). It should be noted that the amount of interleukin-6 in patients of all studied groups was statistically higher than that of the control group. Conclusions. Immune-inflammatory blood changes in pregnant women occur in the case of a severe course of COVID-19 and are accompanied by an increase in the level of interleukin-6 at all stages of the severe course of the disease. СRP is a marker of the severe course of the coronavirus disease in pregnant women. The identified changes are accompanied by coagulopathy and hypercoagulation with increased D-dimer content in patients with a severe course of the disease. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.