Two of the infants had elevated IgG and IgM concentrations. IgM “is not usually transferred from mother to fetus because of its larger macromolecular structure. ... Whether the placentas of women in this study were damaged and abnormal is unknown,” Dr. Zeng and colleagues said. “Alternatively, IgM could have been produced by the infant if the virus crossed the placenta.”
“Although these 2 studies deserve careful evaluation, more definitive evidence is needed” before physicians can “counsel pregnant women that their fetuses are at risk from congenital infection with SARS-CoV-2,” Dr. Kimberlin and Dr. Stagno concluded.
Dr. Dong and associates had no conflicts of interest. Their work was supported by the National Key Research and Development Project and others. Dr. Zeng and colleagues had no relevant financial disclosures. Their study was supported by grants from the National Natural Science Foundation of China and Zhongnan Hospital. Dr. Kimberlin and Dr. Stagno had no conflicts of interest.