Introduction. The spread of the delta strain of the SARS-CoV-2 virus during the third and fourth waves of the pandemic led to the fact that a large cohort of pregnant women and maternity women needed respiratory support, standard treatment methods had no effect, and negative outcomes for the mother and fetus has increased.Purpose of the study. The aim is to determine clinical and laboratory features and maternal outcomes in pregnant women with the coronavirus disease 2019 (COVID-19) and critical lung damage.Materials and methods. A comparative study was conducted, followed by a retrospective analysis of clinical and laboratory features, maternal outcomes in 56 pregnant women with COVID-19 treated in this maternity hospital in the first-fourth wave of the pandemic. The research method is continuous, sequential. The first group (main) consisted of 28 women with severe or extremely severe form of the course of COVID-19 and critical lung damage (more 75 %); The second group (comparison) — 28 pregnant women with a moderate form of the disease and lung damage of 25–50 %. Screening assessment of the degree of endogenous intoxication was carried out. The severity of the disease was determined by the evaluation scale National Early Warning Score (NEWS).Results. Laboratory parameters of patients at admission and at the height of the disease have statistically significant differences in the general blood test, such as higher levels of leukocytes, eosinophils, rod-shaped neutrophils, hemoglobin, as well as lymphopenia and monocytopenia in women of the main group at the height of the disease. At the same time, the hematological indices of intoxication in the main group exceed the value of these indicators in the comparison group by two times. Patients of both groups had high levels of acute-phase markers of inflammation — C-reactive protein and ferritin, — an indicator of tissue destruction of lactate dehydrogenase, however, both at admission and at the height of the disease, these indicators were statistically significantly higher in the group of women with critical lung damage. In general, 20/28 patients (71.4 %) of group 1 had an extremely severe course of the disease, 8/28 (28.6 %) had a severe course. In second group, 28/28 patients (100 %) had moderate-severe NCI (p = 0.000), while recovery was noted in all of them. Outcomes of COVID-19 in women with critical lung damage: recovered — 25/28 (89 %); 3/28 (10.7 %) the patients died from complications of COVID-19 of an extremely severe degree.Discussion. The most frequent laboratory anomaly was leukocytosis and a rod-shaped shift in the midst of the disease in women with critical lung damage, as well as a statistically significant increase in the level of C-reactive protein, lactate dehydrogenase, D-dimer. Pulmonary complications (parapneumonic pleurisy, pneumothorax, pneumomediastinum, hydrothorax, lung abscess) and extrapulmonary complications (encephalopathy, panic attacks, acute liver injury, sepsis, thromboembolic complications) were observed only with critical lung damage.Conclusion. In the laboratory, at the height of the disease, in the group of pregnant women with critical lung damage, leukocytosis and stab shift are statistically significantly more common. Hematological indices of intoxication, leukocyte and hematological, confirm endogenous intoxication at the height of the disease. A statistically significantly higher level of aspartate aminotransferase, lactate dehydrogenase, C-reactive protein, D-dimer is determined upon admission to the hospital and at the height of the disease as markers of systemic inflammatory response and cytolysis, which demonstrates the defeat of several organ systems simultaneously.