Lactation is the process of producing and releasing milk from the mammary glands in your breasts. Lactation begins in pregnancy when hormonal changes signal the mammary glands to make milk in preparation for the birth of your baby. It’s also possible to induce lactation without a pregnancy using the same hormones that your body makes during pregnancy. Lactation ends once your body stops producing milk.
Feeding your baby directly from your breasts is called breastfeeding (or sometimes chestfeeding) or nursing. You can also feed your baby milk that you have expressed or pumped from your breast and saved in a bottle.
Where does human milk come from?
Human milk comes from your mammary glands inside your breasts. These glands have several parts that work together to produce and secrete milk:
- Alveoli: These tiny, grape-like sacs produce and store milk. A cluster of alveoli is called lobules, and each lobule connects to a lobe.
- Milk ducts: Each lobe connects to a milk duct. You can have up to 20 lobes, with one milk duct for every lobe. Milk ducts carry milk from the lobules of alveoli to your nipples.
- Areola: The dark area surrounding your nipple, which has sensitive nerve endings that lets your body know when to release milk. To release milk, the entire areola needs stimulation.
- Nipple: Your nipple contains several tiny pores (up to about 20) that secrete milk. Nerves on your nipple respond to suckling (either by a baby, your hands or a breast pump). This stimulation tells your brain to release milk from the alveoli through the milk ducts and out of your nipple.