When babies are first born, their immune system is not fully developed yet, which leaves them susceptible to illnesses. Antibodies from their mother help provide the protection newborns need in the outside world. The immunity is temporary, but it lasts until a baby is old enough to receive vaccinations.

"Antibodies are proteins that are constantly being made and broken down in the body," said Leann Poston, M.D., MBA, M.Ed., from Invigor Medical in Kennewick, Washington. "Since the baby is not making the antibodies, the ones they receive from their mother break down in a matter of weeks to months. As a result, antibody levels are highest right after birth and decline over the next six to 12 months. They are broken down at different rates depending on the child."

There are various ways antibodies are passed from mother to baby. While in utero, a baby receives antibodies via the placenta. After the baby is born, they can get antibodies from drinking colostrum (the golden