Transplacental Transfer of SARS-COV-2 Antibodies

The transfer of immunoglobulins from the mother to her fetus is the major defensive tool of the neonate against infectious diseases during the first few months of life. The mechanism of antibody transfer is selective, and only maternal immunoglobulins G (IgG) are able to pass across the placental barrier. This mechanism depends on many factors, such as maternal IgG concentration, IgG subtypes, maternal diseases that affect placental integrity, gestational age, and birthweight. The infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) increases maternal, obstetrical, and neonatal adverse outcomes. In contrast, infants with SARS-CoV-2 immunity are protected against the disease-related hospitalization. The aim of this chapter is to review the incidence of transplacental transfer of SARS-CoV-2 and the possible risk factors that could influence this transfer and that are specific to SARS-CoV-2 infection and vaccination.