DETROIT, Mich. ( – Pregnant women are at a higher risk of complications from COVID-19, and a new study finds that it can also harm their unborn child. A team from Wayne State University has found evidence that SARS-CoV-2, the virus causing COVID, can create fetal inflammation even if there is no placental infection.

COVID-19 infection during pregnancy increases the risk of preterm birth, stillbirth, and pre-eclampsia — or high blood pressure which damages the organs.

“Most pregnant women with SARS-CoV-2 infection are asymptomatic or only experience mild symptoms. Regardless, in the first six months of the COVID-19 pandemic, it was documented that infected pregnant women are at an increased risk for hospitalization, mechanical ventilation, intensive care unit admission and preterm birth, but rates of maternal mortality were reported to be similar between pregnant and non-pregnant women,” says Dr. Roberto Romero, chief of the NIH’s Perinatology Research Branch and professor of Molecular Obstetrics and Genetics at Wayne State’s School of Medicine, in a university release.

“More recently, it has been clearly shown that pregnant women are at high risk for severe disease and death, as well as preterm birth. Investigating host immune responses in pregnant women who are infected, even if they are asymptomatic, is timely.”

COVID cuts down on virus-fighting immune cells in pregnant women

The research team tracked the health of 23 pregnant women during the COVID-19 pandemic. Of the 23, 12 tested positive for COVID.

Eight of the 12 women had no symptoms, one had mild symptoms, and three had severe symptoms. After delivery, the researchers analyzed the maternal blood and umbilical cord blood to look at any changes in immune responses.

Their observations showed that SARS-CoV-2 decreased T-cells which help protect against viruses. Viral infection also induced an inflammatory immune response, as seen in the increase of inflammatory markers such as interleukin-8, interleukin–15, and interleukin-10. Newborns showed higher levels of the inflammatory cytokine interleukin-8, even if they did not have a direct infection while in the womb (shown through the lack of evidence indicating a placental COVID-19 infection).

Researchers say their findings show that fetuses are vulnerable to maternal SARS-CoV-2 infection. However, the long-term consequences of high inflammation in newborns are still unknown and require further investigation.

The study is published in the journal Nature Communications.