COVID-19 During Pregnancy Can Lead to Preterm Birth, Study Says

Carolyn Crist

August 11, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Pregnant women who contract COVID-19 face significantly higher risks for complications, including preterm birth, according to a new study of births in California during the second half of last year.

The risk of "very preterm" birth — or less than 32 weeks of gestation — was 60% higher for those infected with the coronavirus during pregnancy. The risk of preterm birth — or less than 37 weeks of gestation — was 40% higher.

"The risk is very real," Laura Jelliffe-Pawlowski, senior author of the study and researcher at the California Preterm Birth Initiative at the University of California at San Francisco, told the San Francisco Chronicle.

"It means you and your baby may start your relationship in the world by being in the hospital much longer than expected," she said.

In the largest analysis of its kind so far, researchers looked at the association between COVID-19 and preterm delivery for more than 240,000 births documented in California between July 2020 and January 2021. About 9,000, or 3.7%, had a positive COVID-19 test during pregnancy.

The preterm birth rate was 11.8% among those who contracted the coronavirus, as compared with 8.7% among those who weren't infected. A COVID-19 diagnosis was associated with an increased risk of "very preterm" birth, preterm birth and early term birth — all before 39 weeks of gestation.

Those who contracted the coronavirus were also more likely to have a preterm birth if they had underlying conditions such as hypertension, diabetes and obesity. With a comorbidity, the risk of "very preterm" delivery increased 160%, and the risk of preterm delivery increased 100%.

"Considering increased circulation of COVID-19 variants, preventive measures, including vaccination, should be prioritized for birthing persons," the researchers wrote.

Overall, coronavirus diagnoses on birth certificates increased for all groups during that time, though COVID-19 disparities for communities of color were apparent during pregnancy as well. COVID-19 rates were highest for Native Americans, Native Hawaiians, Pacific Islanders and Latinas.

"We need to be agile and be able to talk about the multiple ways we can protect women," Jelliffe-Pawlowski told the newspaper.

"We need to talk about employment policies that allow women to stay at home longer, avoid contact with others, work in safe places," she said.


The Lancet Regional Health – Americas: "The association of COVID-19 infection in pregnancy with preterm birth: A retrospective cohort study in California."

San Francisco Chronicle: "Devastating impact of COVID on pregnancy highlighted by large UCSF study."


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.