Comparison of in-hospital mortality of COVID-19 between pregnant and non-pregnant women infected with SARS-CoV-2; a historical cohort study

Objectives This study aimed to compare pregnant and non-pregnant women infected with SARS-CoV-2 disease (COVID-19) in terms of in-hospital mortality. Methods This historical cohort study was conducted on hospitalized women of reproductive ages (15-49 years) infected with SARS-CoV-2 in Fars province, Iran during 15 March 2019-10 May 2021. Results Out of the 5,322 patients, 330 were pregnant. The fatality rate of SARS-CoV-2 was 1.2% amongst pregnant women and 3.5% amongst non-pregnant ones. Pregnant and non-pregnant women reported the same history of smoking, opium use, previous COVID-19 infection, vaccination against SARS-CoV-2, and COVID-19 symptoms (p>0.05 for all). However, the pregnant women were younger and had fewer underlying diseases (p<0.001 for both). The results revealed no significant difference between the two groups regarding in-hospital clinical manifestations including the number of days after the onset of COVID-19 symptoms, mechanical ventilation, and long involvement (cRR; 95% CI=0.99 (0.96-1.02), 1.18 (0.72-2.02), and 0.95 (0.88-1.02), respectively). Nonetheless, Intensive Care Unit (ICU) admission was significantly higher in pregnant women (cRR; 95% CI=2.37(1.85-3.02)). After adjusting for age, history of underlying diseases, and ICU admission, pregnant women showed lower in-hospital mortality due to COVID-19 compared to non-pregnant women (aRR; 95% CI=0.32 (0.12-0.87)). Conclusions Based on the current study findings, pregnant women showed lower in-hospital mortality due to COVID-19 compared to non-pregnant ones. Nevertheless, they should follow the same recommendations as non-pregnant women, avoiding exposure to the virus and receiving medical treatment and vaccination. Further studies are recommended to address the follow-up of recovered pregnant women, their babies, and puerperium.