How milk started coming from breasts?

The breasts start preparing for producing milk during the second half of pregnancy. Some people may even experience discharge of colostrum, or 'white gold', a type of pre-milk, during this period. When the placenta is expelled during childbirth, it causes a reduction in the levels of progesterone, which then triggers an increase in the prolactin hormone. Prolactin, along with other hormones like estrogen and progesterone, stimulates the alveoli (milk sacs) in the breast tissue to produce milk. Additionally, the hormone oxytocin, which causes uterine contractions during labor, also plays a role in triggering the 'milk ejection' or 'let-down' reflex. When a baby suckles, it stimulates the nipple and sends a signal to the brain to release oxytocin, which causes the muscles around the alveoli to contract and release milk.