Only if she is short of food and even then it is rare not to produce enough. A woman will naturally produce breast milk after pregnancy. The milk can dry up if the baby does not suckle enough, the mother is dehydrated, not pumping enough and some medicines can also interfere. In general the more milk is required, the more milk the mother will produce. The mother will slowly stop producing milk as the baby moves onto solids. Some women in the olden days made a career of breastfeeding: they were called wet nurses. She would either have her child and then keep breast feeding after it moved onto solids or have lost her child (early childhood mortality was much more common before proper sanitation, vaccination and modern medicine). The wet nurse would then take up residence in the home of a well off family and feed the family’s baby in place of the mother (who’s milk would dry up due to lack of stimulation of the milk ducts).