Study: COVID-19 infection rates high in pregnant women

This population should be considered at a high risk and be included in Phase 1B vaccination schedules, the authors say.

Media Contact: Barbara Clements -, 253.740.5043

The COVID-19 infection rate among pregnant women was estimated to be 70% higher than in similarly aged adults in Washington state, according to a new study published today in American Journal of Obstetrics and Gynecology. Other key findings include:

  • The study also showed that the number of COVID-19 infections in pregnant patients from nearly all communities of color in Washington was high. There was a twofold to fourfold higher prevalence of pregnant patients with COVID-19 infections from communities of color than expected based on the race-ethnicity distribution of pregnant women in Washington in 2018. 
  • A high number of pregnant women with COVID-19 received their medical care in a language other than English. This indicates that public health outreach to enhance vaccination rates in these communities is crucial.

“Our data indicates that pregnant people did not avoid the pandemic as we hoped that they would, and communities of color bore the greatest burden,” said Dr. Kristina Adams Waldorf, an ob-gyn with the University of Washington School of Medicine and the report's senior author. “We were disheartened to see the higher infection rates in communities of color as well as in patients with limited English proficiency."

COVID-19 vaccine allocation is based priority lists set by each state's department of health, which can vary. In some states, pregnancy is considered a high-risk health condition for COVID-19 vaccine allocation in Phase 1B.  Texas, New Hampshire, New Mexico and Alaska are among the states that prioritize pregnant women for COVID-19 vaccines in schedule Phase 1B.

“The vaccine distribution plans vary quite a bit, state-by-state, and pregnant women are written out of the allocation prioritization in about half of U.S. States. Many states are not even linking their COVID-19 vaccine allocation plans with the high-risk medical conditions listed by the CDC – which include pregnancy, Adams Waldorf said.

“The higher infection rates in pregnant patients, coupled with an elevated risk for severe illness and maternal mortality due to COVID-19, suggests that pregnancy should be considered a high-risk health condition for COVID-19 vaccine allocation in Phase 1B all across the United States,” she added. "The time to act is now.”

She said this study is unique in the United States because it is the first to address the question of infection rates in pregnancy in a large population that represents the majority of pregnancies in the state.  The data can inform vaccine policy and guide public health workers and physicians in trying to mitigate COVID-19 in vulnerable populations.

The multisite study included 35 hospitals and clinics that compose the Washington State COVID-19 in Pregnancy Collaborative led by Adams Waldorf and Erica Lokken, an epidemiologist at the UW School of Public Health. The group identified 240 pregnant women who acquired COVID-19 from March through June 2020. This number represents all such known cases at the collaborating sites, which account for 61% of births in the state each year.

"Higher infection rates in pregnant patients may be due to the overrepresentation of women in many professions and industries considered essential during the COVID-19 pandemic – including healthcare, education, service sectors," said Lokken. Pregnant women may also have larger households, children in daycare or playgroups, and be caregivers within an extended family, she added.

This study data fills critical gaps and provides an important estimate of regional COVID-19 infection rates in the pregnant population, Waldorf said. The Centers for Disease Control and Prevention's estimated infection rates may not be representative, she said.

“COVID-19 case reports are missing pregnancy status in up to 65% of reports for women of reproductive age. As a result, the number of pregnant patients infected with COVID-19 was likely underrepresented in national numbers," the authors concluded.

“When the data is woefully incomplete for specific groups, like pregnant women, it is easy to assume that they haven’t been impacted by the pandemic. This was not the case,” said Adams Waldorf.

Pregnant healthcare workers have received the COVID-19 vaccine, and Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has reported no “red flags” in preliminary data about post-vaccination well-being of this population. 

Adams Waldorf urges pregnant women to discuss the risks and benefits of COVID-19 vaccination with their prenatal care provider. More ob-gyns have begun recommending that pregnant women take the vaccine.

“We want to use information from this study to be more prepared for the next pandemic and to not brush pregnant women to the side. They need to have a seat at the table when it comes to vaccine trials and vaccine allocation,” Adams Waldorf said.

This work was supported primarily by funding from the University of Washington Population Health Initiative, Department of Obstetrics & Gynecology and philanthropic gift funds. This work was also supported by the National Institute of Allergy and Infectious Diseases (AI133976, AI145890, AI143265, HD098713, HD001264, AI120793). Study data were managed by the Institute of Translational Health Sciences at the UW, which was supported by the National Center for Advancing Translational Sciences (UL1TR002319). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or other funders.

For details about UW Medicine, please visit


UW Medicine