Brazil study finds coronavirus in fetus’s vital organs

Results impact medical advice for pregnant women with COVID-19

Published in 27/08/2021 - 14:48 By Elaine Patricia Cruz - São Paulo

A Brazilian study has for the first time shown the presence of the novel coronavirus (Sars-CoV2) in different organs of a fetus—the heart, the windpipe, the kidneys, the brain, and the liver. Previous research had demonstrated signs of the virus in the umbilical cord and the placenta, but this is the first time it is detected in fetal tissues. It was also the first time scientists observed that Sars-CoV2 caused a lung infection in the fetus of a mother that had been infected with the virus.

“Using sophisticated techniques, we managed to demonstrate the presence of the virus in fetal tissue, in an unprecedented fashion. When it assails a pregnant woman, this virus reaches the fetus and may circulate in fetal tissues. In this specific case published by us [in a scientific journal], COVID-19 led the fetus to die, which is rare,” said pediatrician Dr. Arnaldo Prata, from D’Or Research and Education Institute (IDOR), one of the people in charge of the study, heard by Agência Brasil.

The case was reported in the fetus of a 33-year-old woman who was 33 to 34 weeks pregnant and was diagnosed with COVID-19 in October last year. She did not display a severe case of the disease. She had light fever, and body and head aches.

At the time she was diagnosed with the disease, she was advised to socially isolate for 14 days and see a doctor in case her state changed or aggravated. The exams carried out on the same day as the COVID-19 diagnosis did not show any alterations or issues with the pregnancy. At that moment, there was not much knowledge about how COVID-19 behaved in pregnant, unvaccinated women. The study shows this may change soon.


After the isolation period, the pregnant woman returned to the doctor’s office. “Fourteen days after the consultation, she noticed the baby was no longer moving, and she returned to the maternity hospital. That’s when the fetus’s death was ascertained,” Prata said. The family allowed the researchers to study the case.

This study led scientists to observe there were signs of the novel coronavirus not just in the placenta, but also in several organs of the fetus, like the lung. The lung infection did not cause its death, however. According to the researchers, the fetus died from severe thrombosis in the mother’s placenta, which interrupted the flow of blood and oxygen to the child.

“The presence of the virus in fetal tissues does not necessarily imply the fetus was infected with the virus. It could mean that the virus went through the placenta and circulated through the fetus. But we were able to identify through an exam of immunohistochemistry the presence of defense cells, the lymphocytes, in this fetus’s lung. It had pneumonia caused by COVID-19. So the fetus also had a disease caused by this infection. But this was not the cause of death,” he explained.


“It is known that coagulation tends to be more likely during pregnancy. But COVID-19 also tends to increase chances of coagulation. Unfortunately, in this pregnant woman, due to COVID-19, she faced a high state of coagulation. And it took place in the placenta, which was obstructed by clots, which stopped the flow of maternal blood to the fetus,” he explained.

This mother, he went on to say, did not feel any symptoms linked to thrombosis, “Thrombosis can take place in the placenta without the pregnant woman feeling anything. So, the takeaway of this published article is that COVID-19 tends not to be severe for the mother, but it does require attention,” he argued. “The big lesson is, for pregnant women with COVID-19, they need to return [to the doctor] before 14 days [in isolation]. She needs assistance regarding her coagulation markers [like the D-dimer] and infection markers,” he warned.

Four months after the fetus’s death, the mother was subject to new tests to identify whether she had any condition facilitating thrombosis, like thrombophilia, which was not identified by the exams. This, Prata stated, confirmed to researchers that the thrombosis stemmed from COVID-19, which may increase the likelihood of coagulation cases.

Nonetheless, Prata warns pregnant women that COVID-19–linked complications during pregnancy are extremely rare. “Fetal loss in a pregnant woman who contracted COVID-19 is rare. It’s not common. It does exist, but it’s rare,” he said. “We have to be careful about such situations where this can happen,” he pointed out.

In addition, there are vaccines against COVID-19 today that are recommended and are being administered in pregnant women, like Pfizer/BioNTech.

The woman is now pregnant again and has been vaccinated against COVID-19. “She received the shot and is now feeling hopeful,” Prata said.

The study

The study was conducted jointly by researchers from a number of institutes and universities, like the Maternity Hospital School of the Federal University of Rio de Janeiro, the Pediatrics department of the D’Or Research and Education, and the Medicine School of the Federal University of São Paulo, and was published this week on scientific journal Frontiers in Medicine.

Translation: Fabrício Ferreira -  Edition: Valéria Aguiar / Nira Foster

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