Abstract Background The factors contributing to the fatal outcome of COVID-19 in pregnant women remain not entirely clear. We compared the prevalence rates of comorbidities and laboratory test results in pregnant survivors and non-survivors. Methods This retrospective study relied on clinical and laboratory data obtained from medical records of pregnant women with COVID-19 admitted to three hospitals of the Republic of Kazakhstan from 16.07.2021 to 31.01.2022. Overall, we obtained data on 157 pregnant women with COVID-19, of whom 95.9 % survived and 4.1 % died in the hospitals. Results Arterial hypertension was present in 50% of non-survivors vs. 7.9% of survivors (P = 0.001), diabetes mellitus was diagnosed in 16.7% of non-survivors vs. 2.3% of survivors (P = 0.044), and the rate of hyperglycemia was 40% and 7.2%, respectively (P = 0.009). Heart rhythm disturbance was present in 50% of non-survivors vs. 6.4% of survivors (P < 0.001), and already at the time of admission to the hospital, the non-survivors had significantly higher heart and respiratory rates. Laboratory tests showed that non-survivors had higher erythrocytes sedimentation rate, C-reactive protein, leukocyte count, and D-dimer levels (P = 0.001, P < 0.001, P = 0.038, P = 0.014, respectively). The creatinine level was within the normal range in both study groups, but it was relatively higher in the deceased pregnant women (71.3; IQR: 66-251.75) vs. 52; IQR: 43-63; P = 0.001). Finally, a higher proportion of those who died presented with abnormal chest CT as compared with the survivors (33.3% vs. 4.2%, P < 0.001). Conclusions The deceased had a higher rate of comorbidities. Given the vulnerability of pregnant women to COVID-19, it is essential to plan a prospective study to provide insights into the factors that contribute to severe COVID-19 outcomes in pregnant women. Key messages • Determining risk factors for fatal COVID-19 is crucial for effective medical care of pregnant women. • Identifying potential risk factors of fatal COVID-19 among pregnant women could help inform public health policies and clinical guidelines.