Through the umbilical cord.
Naturally-acquired passive immunity occurs when a fetus receives antibodies from its mother through the placenta. It also occurs when a baby receives antibodies through breastmilk.
Because their mothers are immune to it and breast fead
A mother may transfer some IgG antibodies passively through the placenta to the fetus.
I am sure that it does.
Nutrients pass through the placenta into the baby through the umbilical cord.
Passive immunity because the antibodies pass from mother to fetus.
Ellicit drugs, alcohol and nicotine.
food and water
A newborn does not yet have a mature immune system and is often unable to mount an effective immune response. Newborns are generally protected by the antibodies they receive through the placenta before birth and through their mother's breastmilk after birth.
As found in Wikipedia Maternal passive immunity is a type of naturally acquired passive immunity, and refers to antibody-mediated immunity conveyed to a fetus by its mother during pregnancy. Maternal antibodies (MatAb) are passed through the placenta to the fetus by an FcRn receptor on placental cells. This occurs around the third month of gestation.[2] Immunoglobulin G is the only antibody isotype that can pass through the placenta.[2] Immunization is often required shortly following birth to prevent diseases such as tuberculosis, hepatitis B, polio, and pertussis, however, maternal antibodies can inhibit the induction of protective vaccine responses throughout the first year of life. This effect is usually overcome by secondary responses to booster immunization.[3] Passive immunity is also provided through the transfer of IgA antibodies found in breast milk that are transferred to the gut of the infant, protecting against bacterial infections, until the newborn can synthesize its own antibodies.[4] The Maternal Antibodies transferred have a half-life of approximately 14 days, and thus only have an effect for the first months.
blood does not pass across the placenta
Nope. Generally there may be problems only if mother is negative and the father is positive. The antibodies to A/B blood types are too large to pass through the placenta and so cannot hurt the baby.