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Last Updated: Mar 1, 2019


Breastfeeding has many benefits for babies, including improved nutrition and protection from childhood diseases. It even reduces the risk of diabetes later in life. Unfortunately, an infection called mastitis can interrupt breastfeeding or cause the mother to abandon it altogether.

lactiferous ducts highlighted in breast cross-section illustration

Mastitis is an inflammation of the breast characterized by pain, redness, and swelling. It can happen to any woman but is most common in those who are breastfeeding - especially within the first three months after a baby’s birth. It’s a very common condition that affects about one in 10 breastfeeding mothers in the United States.

Mastitis usually isn’t dangerous. But if it’s not treated quickly, it can cause an abscess (pocket of pus) to form inside the breast that may require surgical treatment. In rare cases, breast abscesses can be fatal, though almost all of these deaths occur in developing countries. In HIV-positive mothers, mastitis may increase the risk of spreading the disease to the baby.

The most common problem caused by mastitis is interruption or cessation of breastfeeding. The American Academy of Pediatrics recommends exclusive breastfeeding for the first six months of a baby’s life. However, the pain and exhaustion caused by mastitis may cause a mother to wean her baby before she planned to do so.

Causes and Risk Factors

There are two major causes of mastitis. They often occur together:

Risk factors for developing mastitis include:


Women who are coming down with mastitis often experience flu-like symptoms for a few hours before noticing any breast discomfort:

Breast symptoms appear later and usually affect only one side:

Diagnosis and Treatment

Women who experience mastitis symptoms should see a doctor right away. Early treatment can limit discomfort, minimize interruptions to breastfeeding and prevent complications.

Both obstetricians and primary care providers diagnose and treat mastitis. The mother may also be referred to a lactation consultant for breastfeeding advice and support.

Mastitis is usually diagnosed on history and physical exam. Sometimes a sample of the breast milk is cultured to determine which organism (germ) is causing the disease. The doctor will also rule out other causes of breast soreness, including:

Treatment for mastitis include:

Mothers with mastitis should continue breastfeeding (or if that’s not possible, pumping or hand expressing their milk). Moving fresh milk through the breast will help clear out the infection. Applying warm compresses or showering beforehand can help to empty the infected breast and promote healing.

Women with mastitis should see a doctor again if their symptoms don’t improve within a few days. In these cases, the doctor may want to rule out inflammatory breast cancer, a rare cancer that has symptoms similar to mastitis. This is usually done by a mammogram (imaging test) and tissue biopsy (minor surgery).

With proper treatment and support, almost all women recover from mastitis and are able to continue breastfeeding. During and after recovery, it’s important to make sure the breast is emptied regularly to prevent the condition from recurring.


Good breastfeeding technique helps to prevent mastitis. Some tips for mothers include:


Additional Resources

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Tina Shahian, PhD

Tina is a writer for Innerbody Research, where she has written a large body of informative guides about health conditions.


A communication specialist in life science and biotech subjects, Tina’s successful career is rooted in her ability to convey complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. Tina Shahian’s Linkedin profile.


In her spare time, Tina enjoys drawing science-related cartoons.