How do breasts make milk?
• Your breasts change during pregnancy to prepare for making milk. Your breasts contain milk glands and milk ducts that increase in number, causing your breasts to get larger and fuller. Milk is made in small sacs called milk glands or mammary glands. The milk glands are arranged side by side in small grape-like clusters. The milk glands connect to milk ducts, which are pathways for milk to travel through before reaching your nipples. These small ducts join other ducts and form bigger ducts as they get closer to the nipple. Breast milk flows from the ducts into the sinus (collection area) behind the nipple. It then comes out through 15 to 20 small openings on your nipples. • During the later part of your pregnancy, your breasts start to make and store colostrum. Colostrum (KO-lah-strum) is a substance made by the breasts before they start making milk. It contains protein, vitamins and minerals, and sugar. Your baby will receive colostrum during breastfeeding before your breasts start m