Doctors in France believe they have discovered the first confirmed case of a baby contracting coronavirus in the womb, according to a case study published Tuesday in Nature Communications. While doctors around the world have identified several instances of newborns testing positive for COVID-19, the illness caused by the novel coronavirus, this appears to be the case of a baby contracting the virus before birth.
"We have demonstrated that the transplacental transmission of SARS-CoV-2 infection is possible during the last weeks of pregnancy," doctors from France's Antoine Béclère Hospital noted in their study. Researchers went on to note that transmission through the placenta could cause inflammation of the placenta and lead to the virus making its way into the newborn's bloodstream, potentially leading to inflammation of the blood vessels in the child's brain.
According to the study, a 23-year-old woman was admitted to Antoine Béclère Hospital at University Paris Saclay in March with fever, severe cough, and abundant expectoration. The woman, who was just over 35 weeks pregnant, was confirmed to have COVID-19. Doctors performed an emergency C-section when the fetus began exhibiting signs of distress three days after the woman had been admitted.
Upon the baby's birth, tests of the newborn's blood and umbilical cord blood confirmed the baby was positive for COVID-19. Additionally, doctors found evidence of the virus in both the mother's placenta and amniotic fluid, leading researchers to conclude the child had contracted COVID-19 while in the womb. Doctors told The Guardian tests had confirmed the virus spread from the mother's blood stream to the placenta, where it replicated and infected the child in the womb.
"Unfortunately there is no doubt about the transmission in this case," Daniele De Luca, one of the study's authors and the medical director of pediatrics and neonatal critical care at Antoine Béclère Hospital, told The Guardian. "Clinicians must be aware that this may happen. It's not common, that's for sure, but it may happen and it must be considered in the clinical workout."
According to the study, the mother was discharged in good condition six days after her C-section. The newborn began exhibiting signs of irritability, poor feeding, axial hypertonia or rigidity of the muscles, and opisthotonos, a spasm of the muscles that can cause an arching of the back, three days after birth. Doctors also reported finding evidence of inflammation in the baby's brain, a symptom of coronavirus crossing the placenta and entering the baby's bloodstream in utero. However, these symptoms all improved slowly over the course of another three days and a two-month check up showed further improvement along with normal growth and health.
In comments to The Guardian, De Luca noted that while other doctors have found suspected cases of in utero transmission, this is the first case where enough samples had been collected and tested to confirm the route of transmission. "The reason this has not been demonstrated before is that you need a lot of samples," De Luca explained to the news outlet. "You need the maternal blood, the newborn blood, the cord blood, the placenta, the amniotic fluid, and it's extremely difficult to get all these samples in a pandemic with emergencies all around."
While early research suggested transmission of coronavirus during pregnancy was unlikely, recent studies have concluded otherwise. Earlier this month, findings from a study conducted in Italy led researchers at the University of Milan to conclude it was possible for pregnant people to transmit coronavirus to the fetus. According to Business Insider, researchers collected samples of breast milk, placenta, amniotic fluid, vaginal swabs, and umbilical cord blood from 31 women and found signs of the virus or antibodies in a vaginal swab, a breast milk sample, a placenta sample, and nine cord blood samples.
Still, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine have maintained that vertical transmission of COVID-19 appears to be fairly uncommon.
Although doctors in France noted their findings had confirmed that transplacental transmission was possible in the final weeks of pregnancy, they noted that a lack of readily available definite literature data meant the possibility of transmission also occurring earlier in pregnancy could not be ruled out. Even so, they've sought to emphasize how rare such transmissions likely are.
"The bad news is that this actually happened, and can happen," De Luca told Medical Express. "The good news is that it is rare — very rare compared to the global population."
Vivanti, A.J., Vauloup-Fellous, C., Prevot, S. et al. Transplacental transmission of SARS-CoV-2 infection. Nat Commun 11, 3572 (2020). https://doi.org/10.1038/s41467-020-17436-6
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