which immunoglobulin is the most abundant, protects against bacterial & viral infections and is the only immunoglobulin which passes through the placenta to the developing fetus
Naturally acquired passive immunity occurs when maternal antibodies cross the placenta during gestation, or are passed on to a newborn via the mother's breast milk. Immunoglobulin G (IgG) is the only antibody able to cross the placenta to the fetus. IgG is the most abundant antibody in the human body, representing about 75%â80% of all antibodies. It protects the fetus against infection during gestation and the neonate immediately after birth.