For reasons that are not yet clear, pregnant women infected with the virus that causes COVID-19 are more likely to experience preterm births, pre-eclampsia and other neonatal problems than uninfected women.
A team of Yale scientists decided to study whether the virus could affect the placental tissue of infected pregnant women. Their analysis found that although evidence of the virus in the placenta is sparse, the placenta in infected mothers tended to exhibit a much higher level of immune system activity than in uninfected pregnant women, reports the 22nd. April in the newspaper. With.
“The good news is that the placenta is building a strong defense against infection far away, in the lungs or nasal tissue,” said Shelli Farhadian, assistant professor of internal medicine (infectious diseases) and neurology at Yale. and corresponding co-author. “On the other hand, the high level of activity of the immune system could lead to other deleterious effects on the pregnancy.”
The team led by Farhadian and Akiko Iwasaki, Professor Waldemar Von Zedtwitz of Immunobiology at Yale, analyzed blood and placental tissue in 39 infected and COVID-free pregnant women at different stages of pregnancy. Although they found evidence of the virus in only two samples of placental tissue, they found ACE2 receptors – which the SARS-CoV-2 virus uses to enter cells – in the placentas of most women during of the first trimester of pregnancy. These receptors had largely disappeared in healthy women in later stages of pregnancy.
“It is very important to closely monitor pregnant women who are infected early in pregnancy,” Farhadian said.
The activity of the immune system in the placenta during infections like COVID-19 has not been widely studied and it is not known whether other types of infections behave similarly to SARS-CoV-. 2, she said.
Alice Lu-Culligan is the lead author of the study, which was funded primarily by the National Institutes of Health and the Emergent Ventures Fund at the Mercatus Center at George Mason University.
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Material provided by Yale University. Original written by Bill Hathaway. Note: Content can be changed for style and length.