Can a blocked milk duct cause a breast lump?

A duct can become narrowed when milk is not draining well, sometimes after a change in feeding pattern, pressure on the breast, or an ineffective latch. The area may feel fuller before a feed and soften afterward. A blocked duct does not explain every breast lump, so a new, persistent, or unusual lump deserves clinical assessment, even during breastfeeding. Skin colour, nipple changes, and the presence of fever help a clinician distinguish possible causes.

Continue feeding or expressing in a comfortable way, following your baby’s usual cues; stopping suddenly can worsen breast fullness. Check that clothing, straps, or sleeping positions are not pressing on the area. Rest, drink to thirst, and use a cool pack wrapped in cloth for discomfort. Avoid forceful deep massage or repeated attempts to completely empty the breast, because irritation can increase swelling. A lactation consultant can check positioning and attachment.

Contact a clinician promptly if the lump is becoming larger, redness is spreading, the breast is hot, or you feel feverish or unwell. Seek assessment if the area does not improve with supportive care or if a lump remains after feeding patterns return to normal. A clinician may examine the breast and arrange imaging when needed.

Ask: Does the lump fit a blocked duct or another cause? How long should I monitor it? Could my latch or pump settings contribute? What changes in the skin or nipple should prompt a review? Is imaging appropriate while I am breastfeeding?