Naturally acquired passive immunity

Definition
noun
A passive immunity that is acquired by the fetus or newborn through its mother, and typically lasts the first six months of the newborn’s life.
Supplement
Passive immunity is typically short lived (compared to active immunity). It may be naturally acquired or artificially acquired. Maternal passive immunity is one type of naturally acquired passive immunity wherein the maternal antibodies are passed through the placenta to the fetus during the third month of gestation. Another means is by passing the antibodies in the breast milk when breastfeeding.
Compare: artificially acquired passive immunity
See also: passive immunity