Milk ducts can become blocked when the lactating breasts become very full (engorged) and are not emptied regularly. A blocked milk duct feels like a tender lump on the breast.

You can treat a blocked duct with self-care measures, such as warm, wet compresses or showers and massages before breast-feeding. Empty the breast more effectively by feeding from it first, breast-feeding more often, and using different nursing holds. Using ibuprofen (such as Advil) to reduce swelling can help relieve a blocked duct.

A blocked duct can become infected (mastitis). If you develop signs of a breast infection (mastitis), you may need to call your health professional right away.