A French team has reported transmission of Covid-19 across the placenta after a mother become infected during the last trimester of pregnancy.
Both the mother and her newborn tested positive for coronavirus, according to the report, published Tuesday in the journal Nature Communications.
The woman was admitted to a French hospital in March with symptoms including fever and a severe cough. Genetic evidence of coronavirus were detected in her blood and in nasopharyngeal and vaginal swabs. Doctors decided to deliver the baby by cesarian section.
Tests also detected SARS-CoV-2 in the newborn. And days after birth, the child also developed neurological complications, including irregular muscle contractions. The infant’s cerebral spine fluid tested negative for coronavirus or any other germ. At 11 days after birth, an MRI of the child’s brain showed abnormalities in some white matter regions.
Analysis of the placenta detected coronavirus at much higher levels than in either the mother’s or child’s blood or in the intact amniotic fluid surrounding the fetus before birth. That suggested to the researchers that the virus crossed the placenta and infected the baby in the womb.
The mother was discharged in good condition six days after delivery, and the child was discharged after 18 days. Roughly two months later, the child showed improved neurological condition with an otherwise normal clinical exam, the researchers reported.
Other researchers have described potential Covid-19 transmission during the period immediately before or after birth. The authors of the Nature Communications study said these cases had unaddressed issues, such as an unclear route for transmission of the virus.
“It is important to clarify whether and how SARS-CoV-2 reaches the fetus, so as to prevent neonatal infection, optimize pregnancy management and eventually better understand SARS-CoV-2 biology,” they wrote.