Lactation is the biological process of producing and secreting milk from the mammary glands, primarily to feed and provide nutrition to newborns. It typically begins near the end of pregnancy and continues after childbirth, driven by hormonal changes. The process involves stages of milk production (lactogenesis), followed by maintenance of milk supply (galactopoiesis), and the release of milk triggered by the baby's suckling, which stimulates hormones like prolactin and oxytocin. Lactation also provides immune protection to the young and supports their survival during early life. It can occur naturally in almost all mammals and sometimes can be induced without pregnancy in humans and some other species.