What is oversupply of breastmilk?

Oversupply of breastmilk is when you make more milk than what your baby needs for them to grow and develop. Oversupply is also called hyperlactation or hypergalactia.

During the first few weeks after you give birth, it is normal for your breasts to feel full. Your milk production is still adjusting to your baby’s needs.

Oversupply is different from breast engorgement, because it lasts longer than a few weeks after your baby is born.

Oversupply can make breastfeeding difficult for both you and your baby.

What are the causes of oversupply?

There are many reasons why you may have an oversupply, including if:

• you stimulate production of more milk than your baby needs — this happens if you are expressing and breastfeeding or if you are exclusively expressing milk
• your baby wants to suck for comfort
• you are worried you have a low supply or that your baby is not feeding enough, so you express or feed your baby more than they need
• you take medicine to increase your supply — check with your maternity care provider to see if you need to adjust your medicine
• you take a prescription medicine for another condition that causes oversupply, such as metformin

Sometimes your health professional may not know why you have an oversupply.

How breastmilk oversupply affects your baby

If you have an oversupply, your baby may:

• gain weight very quickly
• struggle to develop a deep and sustained latch
• be very fussy and unsettled at your breast and in general
• choke, cough or unlatch during feeds because of the quick milk flow
• refuse feeding from your breast
• have gastrointestinal (tummy) symptoms, such as spitting up, gas, reflux and green or frothy poo
• have a lot of urine (wee)

How breastmilk oversupply affects you

If you have an oversupply, you might feel:

• your breasts grew more than 2 cups during your pregnancy
• your breasts always feel full
• breast or nipple pain
• you leak large amounts of milk
• you have a very forceful let-down
• you often develop plugged ducts, nipple blebs, mastitis or breast abscesses

Oversupply can make breastfeeding a less pleasurable experience for you and your baby. This can cause some people to think about early weaning. There is no need to stop breastfeeding if you want to continue — speak with your maternity care provider or lactation consultant for advice on how to continue breastfeeding if you have oversupply.

Read more on breast engorgement and how to get relief.

How is breastmilk oversupply diagnosed?

Your doctor can diagnose oversupply by assessing your and your baby’s signs and symptoms.

Your doctor will want to rule out any possible medical conditions that could be causing your oversupply. They may refer you to do a blood test.

It’s important that you get an accurate diagnosis. This is because strategies to manage oversupply often aim to reduce your breastmilk supply.

How is breastmilk oversupply treated?

Oversupply of breastmilk is treated by reducing the amount of milk your body produces. Your body produces less milk when milk is left in your breast.

You can reduce your supply by removing any causes for your oversupply, such as excessive pumping and any medicines or supplements you may have taken to increase your milk production. This is best done with the support of your healthcare professional.

Here are some tips to treat oversupply:

• Try block feeding.
• Limit nipple stimulation — try other ways to comfort your baby. Rather than offering your breast, offer a dummy or try soothing techniques such as rocking, cuddling, singing or massage.
• Medicines to reduce your milk production — your doctor will only prescribe them in severe cases and if other treatments have not worked. They will continue to monitor you to check your progress.
• Managing pain and discomfort — place cool packs on your breasts between feeds or take pain medicines as your doctor advises you.

There is not enough research to suggest that peppermint, sage and other herbs can safely help you reduce your milk supply.

Block feeding

‘Block feeding’ is a method that can help reduce your milk supply in just a few days. Block feeding is when you breastfeed or express from one breast for a specific amount of time.

Here are some tips on block feeding:

• Feed your baby from only one breast at each feed.
• Space feeds out — at least two and a half hours apart.
• At your next feed, change to your other breast.
• Continue this pattern for a few days.
• If your other breast is too full — you can express a small amount of milk to relieve pressure or discomfort. Don’t empty that breast. The leftover milk in the unused breast is a trigger for your breast to produce less milk.

Block feeding ensures that one breast always has leftover milk. This will signal your breasts to make less milk and should help fix the oversupply.

If your milk supply does not respond to block feeding, talk to your doctor or other healthcare professional.

You can help your baby cope with oversupply by feeding them semi-reclined or side-lying. A lactation consultant can guide you.

Resources and support

• The Australian Breastfeeding Association has helpful information about oversupply and lactose overload in babies.
• The Royal Women’s Hospital has a guide explaining how to breastfeed.

Other languages

• The Australian Breastfeeding Association has translated their resources about breastfeeding into a number of community languages.
• HealthTranslations Victoria has a booklet called ‘Breastfeeding your baby’ available in a range of community languages.

Aboriginal and/or Torres Strait Islander peoples

• The Australian Breastfeeding Association has breastfeeding resources for Aboriginal and/or Torres Strait Islander people.

Sexually and gender-diverse families

• The Australian Breastfeeding Association and Rainbow Families have developed a resource on breastfeeding, chest feeding and human milk feeding. It has information and support for the LGBTQIA+ community and aims to be inclusive of all LGBTQIA+ families.