Infections in Pregnancy: Mastitis

Infections in Pregnancy: Mastitis

What Is Mastitis?


  1. Mastitis is an infection of the breast tissue that results in swelling and redness. If left untreated, an abscess may form.
  2. Mastitis can develop when bacteria from your baby’s mouth gets into your breast through your nipple during breast-feeding.
  3. Treatment with antibiotics is usually very effective at clearing up mastitis. In some cases, probiotics may be used.

Mastitis is a breast infection. It commonly develops in breast-feeding women during the first few weeks after delivery. Occasionally, this infection occurs in breast-feeding women several months after the baby is born.

Mastitis develops when bacteria (usually staphylococci or streptococci) from the baby's mouth enter into the breast through the mother's nipple. This causes an infection and inflammation in and around the milk-producing glands. Typically, a woman with mastitis develops a fever and notices pain and redness in one area of the breast. She is likely to develop flu-like body aches and fatigue as well.

How Is Mastitis Diagnosed?

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Mastitis is often easy to diagnose. Reporting the symptoms to your doctor should be enough for them to identify the problem and prescribe treatment. In fact, laboratory tests are seldom needed.

What Are the Complications of Mastitis?

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If not recognized or treated, simple mastitis may progress into a collection of pus called an abscess. Your doctor will suspect an abscess if they find a lump beneath the area of redness on your skin.

The formation of an abscess is rare. Most women see their doctor when they experience breast pain and fever. However, it’s important to identify an abscess because it requires different treatment than mastitis.

What Are the Usual Treatments for Mastitis?

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Mastitis typically responds to antibiotic treatment within 24 hours. Your doctor may prescribe the antibiotic dicloxacillin. If you’re allergic to penicillin, alternatives include erythromycin (Ery-Tab) or clindamycin (Cleocin). Also, you can clear the infection faster with continued breast-feeding or pumping. This will help remove milk from your breast.

If your mastitis doesn’t improve within 48 to 72 hours, you may develop an abscess. In these cases, treatment is more aggressive. A surgeon must lance (by incision) and drain the abscess. This may require a trip to the emergency or operating room. You may also need antibiotics. Depending on the severity of your infection, you may be given the antibiotics intravenously rather than orally.

After the abscess is lanced, a sample of your breast tissue is sent to the laboratory. This will help doctors identify the bacteria that caused the infection. Doctors may also examine the sample to make sure cancer isn’t present. However, cancer is unusual in young women with mastitis.

What is the Outlook for Mastitis?

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Antibiotics are usually effective when treating mastitis. However, in some cases antibiotic-resistant infections can be difficult to treat. In these cases, several antibiotics or probiotics may be prescribed.

Start a medication plan as soon as possible to reduce your risk of forming an abscess. If you follow treatment directions carefully, your case of mastitis will likely clear up within several days.

How Can You Prevent Mastitis?

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Many new mothers find it helpful to speak with a lactation consultant before starting breast-feeding. A lactation consultant can give you information on how to properly breast-feed your baby and avoid breast-feeding problems such as mastitis.

Here are some other tips for reducing your risk of getting mastitis:

  • Make sure you fully drain the milk from your breasts while breast-feeding
  • Allow your baby to completely empty one breast before switching to another
  • Change your breast-feeding position each time
  • Check that your baby latches on properly during feedings

You Asked, We Answered

  • Can mastitis become a recurring problem during breast-feeding?
  • Mastitis may reoccur for several reasons. Some of the factors include:

    • - sore nipples or plugged ducts
    • - a history of breast surgery or lumps
    • - stress or fatigue
    • - low iron (anemia)
    • - breasts that aren’t fully drained (engorgement)  
    • - tight clothing (slows the flow of milk)
    • - cigarette smoking (prevents the breast from emptying completely)
    • - sleep position (may put too much pressure on the breast)
    • - not finishing antibiotics from the original infection
    - Janine Kelbach RNC-OB

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