CHICAGO -- The placentas of multiple women who tested positive for COVID-19 showed signs of injury, according to a new Northwestern Medicine study published Friday.
The two major findings about the placenta injuries include an increase in maternal vascular malperfusion, a medical term that means the blood circulation on the maternal side of the placenta is abnormally delivering the same amount of oxygen to the fetus, and blood clotting within the placenta.
"That's really concerning because we see that same placental finding in a lot of disease states, like fetal growth restriction, preterm birth, preeclampsia or even stillbirth," said Dr. Emily Miller, a co-author of the study and a Northwestern Medicine obstetrician. "Seeing this, even acutely in the setting of SARS-CoV-2 infection, makes us worried that this virus may be affecting the placenta."
Miller said there have been a lot of reports of blood clots during COVID-19 with the general population of patients, and finding clots in the placenta "is kind of the placenta version of that same phenomenon."
The placenta, which develops alongside the fetus to support ongoing and safe growth, acts as the kidneys and the lungs of the fetus while it's inside the uterus, explained Miller. The placenta supplies all of the baby's oxygen, breathes off all the carbon dioxide, supplies all of the baby's nutrients, and eliminates all metabolic waste.
Because the placenta plays such an integral part in healthy fetus development, studying it in pregnant women who had COVID-19 can help determine if the virus can cause certain outcomes.
There have been many epidemiological reports of pregnant women who tested positive for COVID-19 and had pregnancy complications, like preterm birth or preeclampsia. It's hard to know if COVID-19 was the cause of those conditions though because they're so common, explained Miller.
"We often will see some changes in the placenta that can lead ultimately to these clinical manifestations," said Miller. "Trying to look at this intermediate piece, and decide if that intermediate piece is affected, gives us some more support to say, 'These pregnancies in women who are infected with SARS-CoV-2 might be at risk.'"
The study examined the placentas of 16 women who tested positive for COVID-19. Ten of the women received their positive diagnosis when arriving for labor and delivery, and the others got their positive COVID-19 results one to five weeks prior to giving birth, according to the study.
Fourteen patients gave birth at full-term, and one patient delivered prematurely. One patient had a stillbirth at 16 weeks, but doctors can't say if COVID-19 was a cause. All of the babies who were born tested negative for COVID-19 and were normal, healthy weights, the study said.