In breastfeeding or nursing, babies or toddlers receive milk from their mothers' breasts. Following birth, breasts produce colostrum, a thick and yellow fluid, rich with nutrients and antibodies for the baby's immature immune system. Within a few days, the newborn's suckling helps bring in the mother's mature milk. Breastfeeding works as a supply and demand system. Nursing prompts a mother's letdown reflex and triggers her body to create more milk; therefore, the more a woman breastfeeds, the more milk she will produce. Children may receive breast milk directly from the breast or through expression, using one's hands or a manual or electric pump. As suckling from the breast contains advantages over pumped milk, breastfeeding advocates distinguish between milk directly from the breast and expressed milk ...