Causes and Symptoms of Mastitis during Breastfeeding

JanelMS, RD, LDN, CBS

Read time: 5 minutes

What should I know about mastitis while breastfeeding?

  • Causes and symptoms of lactational mastitis in women

  • How to treat or manage mastitis

  • Tips to help prevent or avoid mastitis

Mastitis is inflammation in the breast, which often is either caused by or leads to a bacterial infection.1 Affecting up to 33% percent of breastfeeding women, mastitis during breastfeeding may result in discomfort, chills, and even fever – the last things you need while caring for a new baby.2,3,

The good news is that babies do not get sick from mastitis. Your breastmilk will not harm your little one, so it’s important to keep nursing or pumping through your mastitis if possible!3,4,

Swift evaluation and treatment will make a world of difference. And taking good care of yourself is key for both recovery and prevention. Read on for what to look out for when it comes to mastitis.

What causes lactational mastitis?

Mastitis is most common during the first 12 weeks of nursing.4, But it can also happen to anyone lactating throughout the months or years they breastfeed.

Its most fundamental cause is milk being trapped in the breast and not moving. This restricted milk flow is also called milk stasis.1 Milk not flowing well through the breast allows time for bacteria to grow, which may result in an infection.2,

Sore and cracked nipples (which allow bacteria to enter your system), stress and fatigue (both of which can negatively impact your immune response), and restricted milk flow may all put you at higher risk for mastitis.5,9

Milk flow can be restricted for a number of reasons:

  • Relying exclusively on one feeding position may hamper milk flow whereas changing positions can help insure full draining of each breast.

  • Tight bras or clothing or other consistent pressure (like from a bag strap or seatbelt) may restrict milk flow.

  • Skipping feedings, missed feedings, or a strict feeding schedule may inhibit your milk flow.

  • A baby’s sub-optimal latch or suck when feeding can reduce the effective flow of milk6,7,9

Read more: Top Breastfeeding Latching Tips

Learn about: 6 Breastfeeding Positions for You and Your Baby

What are the symptoms of mastitis?

Common symptoms of lactational mastitis include:

  • Lump in one area of the breast or noticeable hardness of the whole breast10

  • A breast that feels warm or hot to the touch11,

  • A breast that is red with possible red streaks extending outward from the affected area9

  • Flu-like symptoms including fever (101 degrees F or more), chills, and general malaise2,

  • Single-sided symptoms (although you can get mastitis in both breasts at the same time, it usually occurs in one breast at a time)12

Can I get mastitis more than once?

While recurrent mastitis is not common, it is possible to get mastitis more than once.12

Inadequate treatment of a previous mastitis infection, a history of plugged ducts, poor milk drainage, nipple problems (thrush, cracks, milk blisters), or a consistent lack of good nutrition and adequate sleep may put you at risk.12

Think you have mastitis and need some support? Our team of registered dietitians, fellow moms, and lactation specialists are available from Monday – Friday 8 am – 6 pm (ET) and Saturday – Sunday 8 am – 2 pm (ET) to help figure out what may be going on. Chat now!

What’s the difference between mastitis and a blocked duct?

Mastitis and a plugged duct are not the same. A plugged duct is a backup of milk in one (or a few) ducts in your breast.9 The plugged area may feel like a "pea" or a hard spot and may be tender to the touch. You may also be engorged behind the blocked duct with milk that cannot pass through.

With a blocked duct you should not be experiencing the warmth or flu-like symptoms that accompany mastitis. With some massage and continue feedings, the plugged duct(s) will usually clear on their own within 24 hours.7,14

Persistent plugged ducts can lead to mastitis, so be sure to manage them proactively.15

Read more:

Avoiding and Managing Blocked Ducts while Breastfeeding

How do I Avoid and Manage Blocked Nipple Pores?

What should I do if I think I have mastitis?

When it comes to helping resolve mastitis, think of this mantra: Heat, Rest, and Empty the Breast!

Call your healthcare provider immediately if you believe you have mastitis

Sometimes mastitis may require antibiotics, so it’s important to call your healthcare provider right away. And always consult with a healthcare professional before trying any alternative treatments, such as extra vitamin C, raw garlic, or lecithin supplements.

Seek out a lactation consultant

A lactation consultant can help figure out what may have contributed to you developing mastitis and come up with a plan to minimize them. This may help to prevent recurrence of mastitis.

Unfortunately, even if you do everything “right”, know that mastitis can still sometimes happen. Do your best to not miss a feed, and like always, be sure to eat a healthful diet, drink plenty of fluids, and get some rest.16

Continue to breastfeed or pump

Keep the milk flowing while you take care of yourself by breastfeeding or pumping. The infection may get worse, or may even lead to a breast abscess, if you do not continue to remove milk from the breast.1

You can also massage the affected area by gently stroking your breast from the outer edges towards the nipple. Do this while you are breastfeeding or pumping to help milk flow, or even while in a hot (but comfortable) shower.8,12

You can also use a warm compress before or during feedings and pumping.8,

Read more: Top Tips for Breast Pumping

Learn about: How and When to Hand Express

Get plenty of rest

Finding time to relax with a baby isn’t easy, but it’s important to get plenty of rest to help your body heal. Ask your partner, family, and friends for help; whether to watch the baby while you rest or to help you with any other to-do’s.

Learn about: How Can I Cope with Fatigue During Pregnancy and Postpartum?

Probiotics may help

Some new research is starting to link taking the probiotic Lactobacillus salivarius with a reduced risk of mastitis.19,20,21 While more research is needed, specific probiotics appear to be a promising way to help manage mastitis.

Always chat with your healthcare provider before taking any new supplements or medications to ensure this is a safe choice for you.

Stay hydrated and eat well

Remember that breastfeeding women should drink plenty of fluids.17

Making healthy food choices will also help keep you energize and help support your immune system. Emphasize fruits, vegetables, whole grains, lean proteins, beans, nuts, and seeds.18

Read more: Getting the Right Nutrition While Breastfeeding

How can I prevent or avoid mastitis?

There are a few things that will keep milk flowing and help you minimize your chances of getting mastitis:

  • Avoid skipping feedings. If you must miss one, be sure to pump or hand express.

  • If baby suddenly sleeps longer than normal, hand express a small amount (or do a full pumping session) to help prevent engorgement and milk stasis.

  • Avoid wearing tight fitting clothing or bras. Use bras without underwire. Avoid wearing a baby carrier or a bag that presses on one part of your breast for too long. Avoid sleeping on your stomach.

  • Massage all around the breast during breastfeeding sessions to help empty the breast. Use different breastfeeding positions to help fully drain milk from every part of the breast.

  • Meet with a lactation consultant to adjust baby’s latch if it is painful and baby is not able to get a full feed.4,11,12

Let's Chat!

We know parenting often means sleepless nights, stressful days, and countless questions and confusion, and we want to support you in your feeding journey and beyond.

Our Happy Baby Experts are a team of lactation consultants and registered dietitians certified in infant and maternal nutrition – and they’re all moms, too, which means they’ve been there and seen that. They’re here to help on our free, live chat platform Monday - Friday 8am-6pm (ET), and Saturday - Sunday 8am-2pm (ET).Chat Now!

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For more on this topic, check out the following articles:

Which Foods Should I Avoid While Breastfeeding?

Using Nipple Shields Correctly

Navigating nursing strikes

What to do about Sore Nipples while Breastfeeding?