The conversion of milk is a complex physiological process, which simply means that under the influence of hormones, the glandular cells in the mammary glands convert nutrients from the body into milk, which is discharged through the milk ducts to the body. When the fetus is delivered successfully, the estrogen and progesterone in the pregnant woman’s body will suddenly drop and the pituitary gland will begin to secrete the hormone called prolactin. Under the action of prolactin, the breast cells synthesize various proteins and nutrients in the milk, and the mother will experience a feeling of fullness in her breasts, but the milk will not be expelled automatically at this time. When the mother breastfeeds, the lactation and discharge reflexes are stimulated and the milk eventually flows into the baby’s mouth.