Plugged ducts (also called clogged ducts) are one of the more common side effects of breastfeeding. Although these small, firm lumps in your breast can cause swelling and discomfort, they are usually nothing to worry about. An estimated 20 percent of people who lactate experience them at some point.
A duct gets plugged when milk flow is blocked or obstructed at the nipple, where milk is typically released, or deeper in the system of milk ducts. Symptoms can include a firm lump, a warm and painful localized spot, or a wedge-shaped area of swelling anywhere on the breast.
While a duct can get clogged at any point, they are most likely to get plugged during the first six to eight weeks postpartum. A plugged duct typically develops gradually over the course of a few days or a week, and usually in one breast instead of both at the same time.
If your breasts are not draining milk properly, you may experience a build-up or blockage of milk in one or more areas. This can happen due to uneven pressure on one part of the breast from sleeping on one side frequently, feeding in only one position, or always feeding with one breast last. The resulting blockage builds pressure, as more milk is produced, which can lead to inflammation and pain, as well as a lump that may change position over time. (A milk blister, or bleb, might also form around the opening of your nipple, though a bleb is not necessarily caused by a plugged duct.)
First, continue breastfeeding or pumping to fully drain the affected breast. You can also:
When you first notice what you believe is a plugged duct, try to track your symptoms, as it could lead to various breast infections, including an abscess or mastitis1, both of which require immediate attention. Contact your provider if:
1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900741/
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