Clinical evolution of COVID-19 during pregnancy at different altitudes: a population-based study

Background The impact of influenza and various types of coronaviruses (SARS-CoV and MERS-CoV) on pregnancy has been reported. However, the current pandemic caused by SARS-CoV-2 continues to reveal important data for understanding its behavior in pregnant women. Methods We analyzed the records of 326,586 non-pregnant women of reproductive age and 7,444 pregnant women with no other risk factor who also had a SARS-CoV-2 RT-PCR result to estimate adjusted prevalence (aP) and adjusted prevalence ratios (aPR) of COVID-19 and its requirement of hospitalization, intubation, ICU admission and case-fatality rates. Adjustment was done through Poisson regressions for age and altitude of residence and birth. Generalized binomial models were used to generate probability plots to display how each outcome varied across ages and altitudes. Results Pregnancy was independently associated with a 15% higher probability of COVID-19 (aPR: 1.15), a 116% higher probability of its following admission (aPR: 2.169) and a 127% higher probability of ICU admission (aPR: 2.275). Also, pregnancy was associated with 84.2% higher probability of developing pneumonia (aPR: 1.842) and a 163% higher probability of its following admission (aPR: 2.639). There were no significant differences in COVID-19 case-fatality rates between pregnant and non pregnant women (1.178, 95% CI: 0.68-1.67). Conclusion Pregnancy was associated with a higher probability of COVID-19, developing of pneumonia, hospitalization, and ICU admission. Our results also suggest that the risk of COVID-19 and its related outcomes, except for intubation, decrease with altitude.