Objectives

To examine the effect of pregnancy on COVID-19 related in-hospital mortality in reproductive aged women, aged between 15 and 45 years, with SARS-CoV-2 infection confirmed with PCR 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 and hazard ratios of independent factors associated with in-hospital death were calculated.

Results

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

Conclusions

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.

With the adjustment for intervention, pregnancy was found associated with more favorable outcome of COVID-19, in line with the hypothetical protective role of a weaker immune response.