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Risk factors for adverse outcomes among pregnant and postpartum women with acute respiratory distress syndrome due to COVID-19 in Brazil

Our take —

Among 2,475 pregnant women in Brazil with indications of severe COVID-19, a large proportion (24%) either died, was admitted to the ICU, or required mechanical ventilation. In addition to comorbidities known to be associated with adverse COVID-19 outcomes, Black ethnicity and having poor access to health care were risk factors for poor outcomes. The study highlights how social vulnerability and delays in care can lead to severe COVID-19 outcomes among pregnant women, but it is unclear how risks may be different relative to non-pregnant women of a similar age and comorbidity profile.

Study design

Case series

Study population and setting

This study used a Brazilian national surveillance system for acute respiratory distress syndrome (ARDS) to identify 2,475 pregnant and postpartum women with a diagnosis of ARDS attributed to COVID-19 (defined by any laboratory, clinical, or epidemiological criteria) as of July 14, 2020. The surveillance system defined ARDS as the presence of dyspnea, respiratory distress, or oxygen saturation <95% in combination with a flu-like symptom and did not assess lung edema. The authors evaluated risk factors for the composite endpoint of death, admission to the ICU, or mechanical ventilation. Demographic variables, clinical variables, and variables related to health care access were abstracted from the database. Multivariable logistic regression was used to test associations between potential risk factors and the outcome.

Summary of Main Findings

The median age of pregnant or postpartum women with COVID-19-related ARDS was 30 years; 20% were older than 35 years, and 28% had at least one comorbidity. Among all 2,475 women, 590 (24%) had the composite adverse outcome, and 204 (8%) died. Of those who died, 40% were never admitted to an ICU. Multivariable logistic regression was restricted to the 2,184 women with complete data. From this analysis, being postpartum at ARDS notification (OR 2.43, 1.94 to 3.05), obesity (OR 2.12, 1.38 to 3.27), diabetes (OR 1.66, 1.18 to 2.35), Black ethnicity (OR 1.61, 1.06 to 2.44), or age greater than 35 years (OR 1.39, 95% CI: 1.08 to 1.78) was associated with experiencing the adverse outcome. Additionally, several variables related to health care access were associated with the outcome: living in a peri-urban area (OR 3.58, 1.16 to 11.04); living in an area without Family Health Strategy, a program providing primary care through community health workers (OR 2.77, 1.15 to 6.69); and living more than 100 km away from the hospital providing ARDS notification (OR 1.83, 1.23 to 2.73). Results were broadly similar when the outcome was restricted to ICU admission.

Study Strengths

This study drew from a national surveillance system and included a large number of pregnant and postpartum women; it was able to consider several variables related to health care access.


No comparison is available with non-pregnant women with a similar age and comorbidity profile, so it is not possible to determine whether pregnancy conferred an elevated risk of adverse outcome of COVID-19 in this setting. No data were presented on the gestational age at COVID-19 diagnosis, and outcomes may depend on the timing of SARS-CoV-2 infection relative to pregnancy. Without data on the causes of maternal deaths or independent risk factors for mortality such as caesarean delivery (which is particularly common in Brazil), it is not possible to attribute deaths to COVID-19 with certainty. No data were available on whether women had caesarean deliveries, which are particularly common in Brazil; caesarean sections may increase the likelihood of adverse outcomes. Data for at least one variable were missing for a large proportion of women in multivariable logistic regression; these women may differ meaningfully from the included women. The ARDS definition for mandatory disease notification in Brazil was less specific and includes less severe cases than what is typically used to define ARDS; the inferences are therefore more applicable to pregnant or postpartum women with moderate to severe COVID-19. The definition of ethnicity (i.e., as distinct from skin color) was not described. The authors did note that ethnicity was a marker of social vulnerability; however, a more detailed analysis is warranted to discern how race, ethnicity, income, and other potential markers of vulnerability interact to affect COVID-19 outcomes for women in this region.

Value added

This study based on nationwide surveillance data in Brazil provides one of the largest studies to date on COVID-19 outcomes among pregnant women, and includes data related to poor access to health care.

This review was posted on: 3 January 2021