In the case of a mammal such as a human, a pregnant woman gestates a fertilized ovum. A fetus develops from the viable fertilized ovum or "embryo." Gestation occurs in the woman's uterus from conception until the fetus (assuming it is carried to term) is sufficiently developed to be born. The woman experiences labor and gives birth. Usually, once the baby is born, the mother produces milk via the lactation process. The mother's breast milk is the source of anti-bodies for the infant's immune system and commonly the sole source of nutrition for the first year or more of the child's life.
Mother can often apply to a woman other than the biological parent, especially if she fulfills the main social role in raising the child. This is commonly either an adoptive mother or a stepmother (the biologically unrelated wife of a child's father). The term "othermother" or "other mother" is also used in some contexts for women who provide care for a child not biologically their own in addition to the child's primary mother.
