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Mastitis (inflamed breasts) is quite common in women who are breastfeeding. A build-up of milk in your breasts can make them inflamed, red and painful. Sometimes this built-up milk can become infected with bugs (bacteria), which needs to be treated with antibiotics.

If you think you have mastitis, it's important to see your midwife or GP to get it treated.


Some breastfeeding women can get a breast abscess. If you feel any hard, red, and painful areas in your breast, see your GP or midwife as soon as you can.

How to avoid getting mastitis

Newborn at breastThere are several things you can do to avoid mastitis. Make sure your baby is latching at the breast correctly and is effectively removing milk. Ask your midwife to check your technique or consider seeing a lactation consultant.

If you were in St George's for labour, birth or postnatal care, you can book to see a lactation consultant at St George's Breastfeeding Clinic. Phone (03) 375‑6337 to make an appointment.

Being stressed, exhausted, or both can mean your immune system doesn't work so well, increasing your chances of getting mastitis. So try to avoid these if you can. Use any help available to you – before you think you need it – and rest while your baby rests.

Follow your baby's cues or signs that they're ready to breastfeed, and don't miss feeds or cut them short. This helps your breasts to empty of milk, so it doesn't build up and cause mastitis. Signs that your baby is ready to feed can be nuzzling, hand-sucking, or mouthing (where they open their mouth and turn their head). Crying is usually the last cue for feeding, and it may be difficult to get your baby to latch properly if they're crying.

If your breasts are feeling full and uncomfortable, it's okay to wake your baby up to feed. If your baby is too sleepy to feed, you can try expressing a small amount of milk by hand. If you need help with this, ask your midwife, lactation consultant, or breastfeeding support person or organisation.

Avoid giving formula top-ups, as the next time your baby feeds they may not remove enough milk, so increasing your discomfort.

Don't use a breast pump unless you've spoken to your midwife, Well Child nurse, or general practice team about it, as using a breast pump may cause you to make too much milk. Using a breast pump without a good reason has been linked to mastitis and other problems such as damaged nipples.

Watch out for the signs of mastitis, especially if you've had it in the past. Get help as soon as you notice any of these signs:

Treating mastitis

If you have mastitis, your midwife, lactation consultant, or breastfeeding support person will check your feeding technique and how well your baby is feeding. The best way to treat mastitis is to frequently feed your baby from the affected breast, so milk fully drains from it. You may also need pain relief or antibiotics.

It's possible you may need to use a breast pump or express milk by hand, to make sure you're removing all your milk. Your general practice team, midwife, Well Child nurse, or lactation consultant can give you more information on breast pumps.

Techniques to help with mastitis

If you have mastitis, there are several things you can do to help.

Let-down of milk

Let-down (also called milk ejection reflex, or MER) makes the milk available to your baby and happens soon after they start suckling. Your baby's suckling stimulates you to make the hormone oxytocin, which triggers milk let-down. Once the milk is flowing your baby begins to suck and swallow rhythmically.

While you're feeding your baby, more let-downs can happen, but you might not feel these. However, you're likely to notice your baby sucking more vigorously or swallowing more milk. Some mothers don't feel the first let-down, others feel tingling in their breasts, and some have a stronger feeling. All of these experiences are normal.

Blocked duct

If you have a blocked duct you may feel a painful area in one breast. You may also feel a lump. If you don't have any other symptoms, continue breastfeeding, apply heat to the affected area, massage it gently, and rest as much as possible.

Let your midwife, GP, lactation consultant, or other breastfeeding support person know if it doesn't get any better or if you start feeling unwell. Symptoms such as a headache, aches and pains, and feeling like you're coming down with the flu or a cold may mean that you have an infection that needs further treatment.

When you have a blocked duct or a breast infection, it's important that your baby breastfeeds effectively and often, to remove milk from your breasts.

Written by HealthInfo clinical advisers. Last reviewed February 2018. Last updated June 2019.


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Review key: HIBRF-24381