A small preliminary study from Northwestern Medicine suggests that a blood test may identify the risk of stillbirth and placentitis in pregnant individuals who have had Covid-19. Research has shown pregnant people with the virus have a higher risk of stillbirths and other pregnancy complications.
Northwestern’s Dr. Leena Mithal, the paper’s first author, said, “Right now, we don’t know if there’s placentitis until after the fact. We’re laying the groundwork for further studies so that in the future, people who are diagnosed with Covid during pregnancy may be able to get a test that will help identify pregnancies that may be at higher risk of stillbirth or fetal distress.”
Scientists identified a link between Covid placentitis, in which the virus infects the placenta, but can only diagnose instances of placentitis after delivery by examining the placenta. Placentitis affects between one per cent and two per cent of pregnant people infected with Covid-19. Unlike many pregnancy complications, the risk of placentitis and stillbirth isn’t linked to the severity of the virus.
Using a biorepository of blood taken from pregnant people during the pandemic in 2020, the scientists looked at the blood of participants who had tested positive for Covid-19 during pregnancy - six who were positive for placentitis and 12 controls who were not. Out of those who had placentitis, two had low levels of viral RNA (called viremia) in their blood; none of the controls did. One of the people with viremia had a stillbirth, and the other had a good infant; all participants who tested negative for the marker delivered healthy babies.
Dr. Elisheva Shanes, a co-investigator of the study and assistant professor of perinatal and autopsy pathology at Feinberg, said, “The part of the placenta infected by the virus is also the part that’s in contact with maternal blood. So if there’s an infection in these cells, the virus may also be found in the blood. If a pregnant person had Covid and no placentitis, we wouldn’t expect to find the virus in the blood.”
The authors said the best way to protect both the parent and baby is to get vaccinated. Mithal said, “We don’t know why viremia does or doesn’t affect some people, but the vaccine does seem to protect against severe complications.”
