Blocked milk ducts

Blocked Milk Ducts: Causes and Effective Actions

The feeling of a painful, hard lump in the breasts that does not disappear after feeding can be a sign of a blocked milk duct (or lactostasis). This is a very common problem among nursing mothers, causing significant discomfort and, if ignored, can develop into a more serious complication — mastitis. Understanding the causes and the correct action algorithm will help quickly deal with this problem.

What is a blocked duct?

The mammary gland consists of many lobules where milk is produced. From each lobule thin milk ducts lead to the nipple. A blockage occurs when one of these ducts is obstructed and milk cannot flow freely. As a result, milk stasis forms in that area of the breast, leading to inflammation, swelling, and pain.

Main causes of blockage:

• Ineffective breast emptying: This is the primary cause. It can be caused by improper baby positioning, infrequent or short feedings, or when the baby prefers one breast.
• External pressure: Too tight a bra (especially with underwire), sleeping on the stomach, tight bag straps, or car seats can compress the ducts.
• Missed feeding or pumping: This leads to breast overfullness and increases the risk of stasis.
• Stress and fatigue: They can affect the oxytocin reflex responsible for milk let‑down.

How to distinguish from mastitis?

A blocked duct is the first stage that can precede mastitis. Main differences:

• With lactostasis there is usually no high fever or flu‑like symptoms (chills, weakness).
• Pain and redness are more localized, often a distinct “lump” is felt.

If fever and a marked worsening of well‑being accompany these symptoms, it is likely already mastitis, and you need a doctor’s consultation. Learn more about feeding problems using our tool "Breastfeeding Solutions".