What Is Mastitis?

Woman holding her breast, wincing in pain

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Mastitis is often called a breast infection. It's the swelling (inflammation) of the breast alone, or along with an infection. Mastitis is a common problem of breastfeeding. It affects up to 20% of nursing mothers. It's more likely to happen within the first six weeks after the birth of your baby, but it can appear at any time while you're breastfeeding.

Mastitis Symptoms

Signs and symptoms of mastitis include:

  • Pain
  • A swollen, tender, warm area on the breast
  • Redness in the location of the swelling
  • Fever
  • Chills
  • Flu-like symptoms
  • Fatigue
  • Body aches
  • Nausea


You can get mastitis from an infection. Bacteria or other microorganisms can enter your body from cracked nipples, or any opening in your skin. Once bacteria finds its way into your breasts, it can cause an infection.

Another way you can get mastitis is by not removing the breast milk from your breasts regularly and efficiently. Breast milk may not drain from your breasts well when:

Breast engorgement and plugged milk ducts are two other common breastfeeding concerns that can lead to mastitis. Mastitis can also be caused by: 


If you think you have mastitis, notify your doctor as soon as possible. Your doctor will examine your breasts.


Your doctor may prescribe an antibiotic. Don't worry about taking an antibiotic to treat mastitis, your doctor will prescribe one that's safe to use while you're breastfeeding. Medication, rest, and the regular removal of the breast milk from your breasts will help you to recover more quickly.

With immediate treatment, you should begin to feel better within 48 hours.

Continue Breastfeeding

If you have a healthy full-term baby, you DO NOT have to stop breastfeeding if you have mastitis. It's safe to breastfeed while you have mastitis; it will not harm your baby or interfere with the healing of your breasts. 

In fact, the best way to treat mastitis is to keep the breast milk flowing from your breasts by breastfeeding very often. If you cannot breastfeed, use a breast pump or hand express the milk from your breasts every few hours.

Your breast milk changes during mastitis. There is a rise in the levels of lactoferrin and antibodies such as secretory immunoglobin A (IgA). These immune protecting substances protect your baby while you have an infection.

Sodium and chloride levels also go up which can make your breast milk taste salty.

Some infants don't like the change in the flavor of the breast milk and may refuse to breastfeed on the side with the mastitis. 


Follow these suggestions and guidelines for breastfeeding with mastitis:

  • Continue to breastfeed or express your breast milk frequently. Breastfeeding is the best way to drain your breasts and relieve engorgement and plugged milk ducts.
  • Start breastfeeding on the side that has the swelling. Your baby's suck will be stronger at the beginning of a feeding which may help to remove the breast milk and any clogged areas in your breast.
  • If breastfeeding on the side with the mastitis is painful, it could interfere with your let-down reflex. If you're having trouble with let-down, move your baby to the other breast until let-down begins then put the baby back on the painful breast.
  • Make sure that you're positioning your baby at your breast correctly, and your baby is latching on properly. With a good latch, you're less likely to develop sore, cracked nipples, and your baby can remove the milk from your breasts and drain your breasts much better.
  • Latch your baby on with her nose or chin pointing toward the clogged area of your breast. This position will help to remove the breast milk from that particular spot.
  • Change your breastfeeding positions each time you breastfeed to help empty the different areas of your breasts.
  • Massage the swollen, tender area to help loosen any breast milk that's clogged there. Start massaging the breast at the affected area and work your way up to the nipple.
  • Pump or hand express after breastfeeding to remove even more breast milk.
  • Get enough rest.
  • Drink plenty of fluids.
  • Eat a healthy, balanced diet.
  • Place a warm compress on your breast or take a warm shower before breastfeeding to help with your let-down reflex and the flow of breast milk.
  • A cold compress or cold cabbage leaves can be used after each feeding to relieve pain and swelling.
  • Ask your doctor if you can take Tylenol (acetaminophen) or Motrin (ibuprofen). These over-the-counter medications can decrease pain and swelling.
  • If your doctor gives you a prescription for an antibiotic, make sure to follow all the directions and take it for as long as it's prescribed to prevent the infection from coming back.


You can’t completely prevent mastitis, but there are steps you can take to try to lower your risk of developing it.

Use proper breastfeeding technique: When your baby is correctly latched on, he can remove your breast milk better, and he is less likely to cause damage to your nipples.

Alternate feeding positions: Different nursing positions drain different areas of the breast which helps to prevent breast milk from getting clogged in certain areas.

Change breast pads often: If you wear breast pads for leaking, make sure to change them frequently to stop the growth of bacteria. Wet breast pads can also break down the skin on your nipples, creating an entrance for infection.

Do not allow your breasts to become engorged: Nurse your baby, pump, or hand express your breast milk very often to prevent breast engorgement and plugged milk ducts, which can lead to mastitis.

Do not wear a tight bra: Tight bras or anything that confines, restricts or puts pressure on your breasts can cause a breast infection.

Wean your baby gradually: Abrupt weaning can cause breast engorgement. But, if you wean your baby slowly, your milk supply will gradually go down, lessening the chance for engorgement, plugged ducts, and mastitis.

Take care of yourself: Try to eat healthily, get enough calories, stay hydrated, and get enough rest. Stress and fatigue are risk factors for mastitis.


If your symptoms do not get better on their own within 24 hours, it's important to contact your doctor. A delay in treatment can lead to complications, such as:

Early Weaning

The development of mastitis may cause some women to consider weaning. Nursing with mastitis is safe, and it helps to clear the infection, so it's not necessary to stop breastfeeding. Actually, the sudden end of breastfeeding can make mastitis worse, and it's more likely to lead to an abscess.

Breast Abscess

An abscess is a tender, fluid-filled lump that can form in your breast as a result of mastitis. If you develop an abscess, your doctor may need to remove the fluid with a needle, or you may have to have minor surgery.


Thrush is a fungal or yeast infection. Yeast is naturally present on and in our bodies, but when it overgrows or moves to a place it shouldn't be, it can become a problem. Thrush can cause a breast infection by getting into the breast through damaged nipples, but it can also develop as a result of mastitis.

A Word From Verywell

The use of antibiotics to treat a breast infection can lead to an overgrowth of yeast. A yeast infection can cause red, burning nipples and breast pain, or you may see white patches or redness in your baby’s mouth.

If you see thrush on your nipples or in your child’s mouth, call the doctor. Both you and your child will need treatment with an anti-fungal medication. And, since yeast spreads quickly and is difficult to get rid of, it's possible that other family members may need to be treated as well.

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  1. U.S. Department of Health & Human Services. Your Guide to Breastfeeding. Updated October 8, 2018.

Additional Reading
  • Spencer, J. P. (2008). Management of Mastitis in Breastfeeding Women. American Academy of Family Physicians, 78(6), 727-731.

  • Academy of Breastfeeding Medicine. (2014). Clinical Protocol #4: Mastitis.
  • Lawrence, Ruth A., MD, Lawrence, Robert M., MD. (2011). Breastfeeding A Guide For The Medical Profession Seventh Edition.  Mosby.
  • Riordan, J., and Wambach, K. (2014). Breastfeeding and Human Lactation Fourth Edition. Jones and Bartlett Learning.