Factors Associated with Hospitalization with Symptomatic COVID-19 Illness Among Pregnant Individuals: A Multi-Center Retrospective Cohort Study

Data indicate that pregnant individuals face higher risk of hospitalization, serious illness, and even death from SARS-CoV-2 infection.  Infection with SARS-CoV-2 also could pose a higher risk of pregnancy complications.  Identifying risk factors for severe COVID-19 illness during pregnancy can inform COVID-19 vaccination counseling and messaging for people who are pregnant.

This study of 19,456 pregnant individuals with an estimated due date March 1, 2020-February 28, 2021, found a number of factors associated with hospitalization. Of this group, 75 (0.4 percent) were hospitalized with symptomatic COVID-19, and the associated factors included: Hispanic ethnicity, native Hawaiian or Pacific Islander race, age (younger than 25 years), pre-pregnancy obesity, diagnosis of a metabolic disorder, lung disease excluding asthma, and cardiovascular disease. Study participants were a cohort of pregnant individuals who received prenatal care at three healthcare systems in the U.S.: Kaiser Permanente Northern California, Kaiser Permanente Northwest in Oregon and Washington, and Baylor in Texas. Data were collected primarily through medical record extraction.

Although hospitalization with symptomatic COVID-19 was uncommon, pregnant individuals should be aware of the risk factors associated with severe illness. The risks from underlying health factors underscore the importance of COVID-19 vaccination. Findings on racial disparities highlight the importance of studies to identify social determinants that may increase risks for COVID-19 exposure. The findings also suggest the need for outreach to communities disproportionately affected by COVID-19 to provide information about disease prevention.

Previous studies assessing risk factors for severe COVID-19 differed from our approach. They have largely been from one point in time or from a single center. Our study included three sites and captured data from the first antenatal visit to the end of pregnancy. We also used standard disease classification codes to distinguish symptomatic COVID-19 hospitalizations from hospitalizations with incidental detection of SARS-CoV-2 by routine screening.