ANATOMY

Detailed explanation-1: -During the last 3 months of pregnancy, antibodies from mothers are passed to their unborn babies through the placenta. This type of immunity is called passive immunity because the baby has been given antibodies rather than making them itself.

Detailed explanation-2: -Humans have three types of immunity-innate, adaptive, and passive: Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection. For example, the skin acts as a barrier to block germs from entering the body.

Detailed explanation-3: -Naturally acquired passive immunity occurs during pregnancy, in which certain antibodies are passed from the maternal blood into the fetal bloodstream in the form of IgG. Antibodies are transferred from one person to another through natural means such as in prenatal and postnatal relationships between mother and child.

Detailed explanation-4: -Placental transfer of maternal IgG antibodies to the fetus is an important mechanism that provides protection to the infant while his/her humoral response is inefficient. IgG is the only antibody class that significantly crosses the human placenta.