Is pregnancy a risk factor for in-hospital mortality in reproductive-aged women with SARS-CoV-2 infection? A nationwide retrospective observational cohort study.

Objective: To examine the effect of pregnancy on coronavirus disease 2019 (COVID-19) -related in-hospital mortality in women of reproductive age (between 15 and 45 years), with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed with polymerase chain reaction tests, adjusted for factors such as co-infection and intervention that were not considered in existing literature.

Methods: Data gathered from a nationwide database in Brazil were analyzed using multivariate logistic regression and multivariate Cox regression. Adjusted odds ratios and hazard ratios of independent factors associated with in-hospital death were calculated.

Results: A total of 97 712 women were included in the study. After the adjustment for sociodemographic factors, epidemiologic characteristics, pre-existing medical conditions, and intervention, pregnant women were found to be associated with lower risk for in-hospital mortality as well as longer survival time compared with non-pregnant women. When covariates of intervention were omitted from the analysis, pregnancy did not appear to be a significant factor associated with mortality.

Conclusion: With the adjustment for intervention that was shown to be an independent factor associated with mortality, pregnancy appeared to have a favorable effect on SARS-CoV-2 infection. Given the immunosuppressed state of pregnancy, this finding is in line with the hypothetical protective role of a weaker immune response that inhibits the production of proinflammatory cytokine.