IN PREGNANT women who tested positive for SARS-CoV-2, the virus that causes COVID-19, male placentas showed increased immune activation compared with female placentas.
A new study published Wednesday, in Science Translational Medicine said the significantly higher levels of certain genes and proteins associated with increased immune activation may help protect male fetuses from becoming infected with SARS-CoV-2 in utero. But the resulting inflammation could pose risks to the fetus and child, notes Andrea Edlow, senior author of the study and maternal-fetal medicine specialist at Harvard-affiliated Massachusetts General Hospital (MGH).
This is the first study to look at sex differences in the transfer of a mother’s antibodies from COVID infection to her fetus, and the first to examine sex differences in the placental response to maternal infection.
Pregnant women with COVID-19
transferred significantly less immunity to the virus to male fetuses than to female fetuses, which could affect an infant’s risk for becoming infected with SARS-CoV-2.
“The sex of the fetus influenced both the mom’s ability to generate antibodies to COVID-19 and to transfer them to her baby,” says Edlow.
Epidemiological studies have shown that male adults, children, and infants have a higher prevalence of COVID-19 infection and develop more severe disease than females. Male fetuses and infants are also more vulnerable to a host of pre- and perinatal exposures compared to female babies, so Edlow and her team sought to examine placentas, maternal blood and cord blood from pregnancies affected by maternal SARS-CoV-2 infection.
The study included 68 pregnant women, of whom 38 became infected with SARS-CoV-2 during their third trimester prior to the development of the COVID vaccine. The remaining 30 pregnant women who tested negative for SARS-CoV-2 in pregnancy. In both groups, half the fetuses were male and half were female.