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New study differentiates perinatal risks of COVID-19 infection from pandemic era societal changes

California preterm births declined during pandemic

A new study has disentangled the risks to infants and birth parents from infection with SARS-CoV-2—the virus that causes COVID-19— from risks related to broader societal changes during the pandemic period.

Led by Dr. Shelley Jung, a UC Berkeley School of Public Health researcher, and published today in JAMA Network Open, the article shows that COVID-19 infection was associated with increased risk of preterm birth, hypertension, and severe maternal morbidity—which the CDC defines as “unexpected outcomes of labor and delivery that result in significant short- or long-term consequences to a woman’s health.” Interestingly, the pandemic period itself was associated with a lower risk of preterm birth, but a higher risk of hypertension and gestational diabetes.

This is the first study to separate the infant and birth parent risks linked to the pre-pandemic period, the societal changes of the pandemic period, and individual COVID-19 infection. “As far as we know, ours is the first within one coherent set of data to pull these three groups apart,” said Dr. Jennifer Ahern, a UC Berkeley epidemiology professor and the paper’s senior author.

The societal changes that may have affected health included differential access to care, economic strain, physical inactivity, and other stressors.

“It was an extremely stressful time for people for a variety of reasons,” said Ahern. “There were the economic impacts, which were pretty substantial, people losing jobs and sources of income.”

Jung noted that while COVID-19 infections had negative effects, the pandemic did also bring some positive impact.

“You’ve got maybe less commute stress, less physical stress during pregnancy,” she said. “It’s just a very complex set of changes that all coincided. It was exciting to dig into the net effect of the period on the people of California.”
This study examined statewide California data, individually linking all birth and hospital discharge records for 2019 to 2020.
“We linked the birth records to the hospital records,” Jung said. “Then we looked nine months back at the birth parent’s pregnancy and looked at all the hospital visits during those nine months.”

Ahern praised the state of California for coordinating data sources and making them available through a rigorous process that she said allows for valuable research while also protecting patient privacy.

The team will move on to look not just at the overall effect of the COVID pandemic period on the population, but how COVID may affect health disparities.

Additional authors include: Emily F. Liu, Mahasin S. Mujahid, and William H. Dow of UC Berkeley School of Public Health and Dana E. Goin and Kara E. Rudolph of Mailman School of Public Health at Columbia University.

This project was funded by grants from the National Institutes of Health.