Maternal COVID-19 Infection Raises Risks of Low Birth Weight, Preterm Birth, and Stillbirth

Women who contracted COVID-19 while pregnant were more likely to have poor birth outcomes, including low birth weight, preterm birth, smaller babies,, and stillbirth, according to new study results published in The Lancet Digital Health.¹

Investigators from the Institute for Systems Biology (ISB) examined the electronic health records of more than 18,000 women with SARS-CoV-2 tests during pregnancy. They compared the outcomes of unvaccinated women with a positive test during pregnancy to those who tested negative.¹

There were 882 women with a positive test during pregnancy.¹

“We found that SARS-CoV-2 infection indicated increased rates of preterm delivery and stillbirth, largely driven by first and second trimester infections,” Samantha Piekos, PhD, first author of the study said in a statement. “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.”¹

Women in the study had mild or moderate SARS-CoV-2 infections. The severity of maternal COVID-19 infection was not correlated with gestational age at delivery.¹

Additionally, poor birth outcomes were present, even if maternal COVID-19 did not result in severe respiratory problems during infection.¹

Women in the SARS-CoV-2-positive cohort were more likely to have Hispanic ethnicity, higher body mass index, lower education attainment, Medicaid insurance, race other than Asian or White, Medicaid insurance, younger age, and other factors known to be associated with negative birth outcomes. To account for this and to make a true apples-to-apples comparison, investigators used a statistical matching technique that controlled for the confounding variables.¹

“Pregnant people are at an increased risk of adverse outcomes following SARS-CoV-2 infection, even when maternal COVID-19 is less severe, and they may benefit from increased monitoring following infection,” Jennifer Hadlock, MD, corresponding author of the paper and assistant professor at ISB, said in a statement.¹

“Both maternal and fetal health are at increased risk with COVID-19. Therefore, this reinforces the importance of protecting pregnant women,” Hadlock said.¹

The study was conducted before COVID-19 vaccines were widely available in the United States.¹

There is an opportunity for future studies to examine whether vaccination helps to prevent negative birth outcomes in breakthrough cases, according to the statement.¹

According to the results of a different study by the CDC released in December 2021, within the 15-jurisdiction reporting area, the intensive care unit admission rate was 0.7% among mothers with COVID-19 and 0.1% among mothers without COVID-19.2

References

1. Maternal COVID-19 infection increases risks of preterm birth, low birth weight and stillbirth. EurekAlert. News Release. January 13, 2022. Accessed January 17, 2022. https://www.eurekalert.org/news-releases/940002

2. Martin, J, Osterman, M, Valenzuela, C. Maternal and infant characteristics and outcomes among women with confirmed or presumed COVID-19 during pregnancy: 14 states and the District of Columbia. National Viral Statistics System. December 2021. Accessed January 18, 2022. https://www.cdc.gov/nchs/data/vsrr/VSRR-17.pdf