Risk Factors Associated With Worse COVID-19 Outcomes in Pregnancy

Pregnant woman with face mask standing in front of window.
A team of investigators assessed risk factors associated with severity of COVID-19 illness in pregnant women.

Older age and underlying medical conditions may be risk factors associated with increased illness severity in pregnant women with COVID-19, according to study results published in Clinical Infectious Diseases.

Although pregnant women with COVID-19 have been determined to be at increased risk for severe illness compared with nonpregnant women with COVID-19, data to characterize related risk factors are scarce.

A team of investigators for the Surveillance for Emerging Treats to Mothers and Babies Networks (SET-NET) therefore conducted an analysis to assess risk factors linked to COVID-19 illness severity in women with confirmed SARS-CoV-2 infection from March 29, 2020, to March 25, 2021.

Of the 16,695 pregnant women with confirmed SARS-CoV-2 infection with data submitted to SET-NET, 7950 women were included in the study. The majority of women (91.2%) were between the ages of 20 and 39 years, 42.0% were Hispanic/Latina, and at least 1 underlying medical condition was reported in 36.4% of the women. The most commonly reported underlying medical condition was prepregnancy obesity (28.2%); 10.6% of women reported having gestational diabetes, and 10.8% of women reported having gestational hypertension. Based on the first positive test or symptom onset, the majority of women had SARS-CoV-2 infection confirmed in their second (29.0%) or third (57.9%) trimester.

In a crude analysis compared with pregnant women who were younger than 20 years, women who were aged 25 to 29 years (risk ratio [RR], 1.32), 30 to 34 years (RR, 1.43), 35 to 39 years (RR, 1.53), and 40 years and older (RR, 1.66) were determined to be at increased risk for moderate to severe critical illness.

Compared with pregnant women who did not work in healthcare, pregnant women who worked in healthcare were determined to be at increased risk of moderate to severe or critical illness (RR, 1.25). Prepregnancy obesity (RR, 1.36), chronic lung disease (RR, 1.37), chronic hypertension (RR, 1.45), and prepregnancy diabetes mellitus (RR, 1.66) were also associated with increased risk for moderate to severe or critical illness.

Compared with women without any underlying health conditions, the presence of any health condition (either underlying medical or related to pregnancy) or 2 health conditions was associated with a 39% and 59% increase, respectively, in the risk for moderate to severe or critical illness. Three or more health conditions were associated with more than double the risk (RR, 2.31).

Gestational diabetes, gestational hypertension, race/ethnicity, trimester during which SARS-CoV-2 infection occurred, cardiovascular disease, and immunosuppression were not found to be significant risk factors for moderate to severe or critical illness in pregnant women compared with women without these conditions who were not pregnant.

“These data can help counsel pregnant women about their risk for moderate-to-severe or critical COVID-19 illness and guide their choice of prevention strategies, target public health messaging, and inform decisions around resource allocation. It is important that pregnant women are informed of their increased risk for severe COVID-19 illness, the signs of severe COVID-19 illness, and strategies for prevention, including vaccination,” the researchers concluded.


Galang RR, Newton SM, Woodworth KR, et al; for the CDC COVID-19 Response Pregnancy and Infant Linked Outcomes Team. Risk factors for illness severity among pregnant women with confirmed SARS-CoV-2 infection – Surveillance for Emerging Threats to Mothers and Babies Network, 22 state, local, and territorial health departments, March 29, 2020 -March 5, 2021. Clin Infect Dis. Published online May 22, 2021. doi:10.1093/cid/ciab432