Let-down is the process by which milk is released from the milk glands to the milk ducts in preparation for breast-feeding. When a breast-feeding woman's breasts are stimulated by suckling or pumping, the pituitary gland produces the hormone oxytocin, which triggers the let-down reflex.

Signs of let-down include:

• A tingling sensation in the nipples, sometimes with mild pain.
• Milk leaking from the breast before nursing or pumping, or leaking from one breast while the baby is nursing at the other breast. Some women may experience let-down when they hear a baby cry.
• Uterine cramps during nursing.
• Increased vaginal bleeding during or just after nursing or pumping the breasts.