People who contracted COVID-19 while pregnant were more likely to have poor birth outcomes including preterm birth, small for gestational age, low birth weight, and stillbirth. The poor outcomes of preterm birth and stillbirth were observed primarily with those infected with SARS-CoV-2 during the first or second trimester, whereas increased rates of small for gestational age were driven largely by third trimester infection.
An Institute for Systems Biology-led study examined the electronic health records of more than 18,000 people with SARS-CoV-2 tests during pregnancy. Researchers compared outcomes of unvaccinated people with a positive test during pregnancy—882 in total—to those who tested negative.
"We found that SARS-CoV-2 infection indicated increased rates of preterm delivery and stillbirth, largely driven by first and second trimester infections," said Samantha Piekos, Ph.D., first author of the study. She added: "The single greatest predictor of gestational age at delivery is gestational age at infection, with earlier age at infection associated with earlier age at delivery."
The study results were used by the Centers for Disease Control and Prevention to support the use of booster shots.