Production of milk by female mammals after giving birth.
The milk is discharged by the mammary gland s in the breasts. Hormones triggered by delivery of the placenta and by nursing stimulate milk production. Colostrum (milk that the mother produces in the first few days after giving birth) has more proteins, minerals, and antibodies and fewer calories and fats than the mature milk that develops later. Mature milk supplies nutrients, hormones, and substances that provide the infant with immunity against infectious agents. Most physicians recommend that babies be fed mother's milk exclusively for the first six months and that nursing continue through the first year. As the child is weaned, lactation tapers off; while nursing continues, fertility is reduced. Problems with lactation may involve hormones, suckling pattern, physical difficulties, or emotional factors. Mothers taking certain drugs or with some diseases (e.g., AIDS ) should not nurse, because of risks to the baby.