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How much do I need to express?

Many mums ask this question


How much you need to pump may depend on why you're doing it and how much baby drinks. 


If it is to relieve engorgement, you may only need to express enough to feel comfortable. If you are expressing for a premature baby or because you’re returning to work, you will need to express fully and frequently. 

Here are some other reasons...

Reasons for expressing

You might express because

  • Your baby is premature or unable to suck well

  • Your baby is in hospital and you can't be there for every feed

  • You are in hospital and your baby can't be there for every feed

  • You're planning to go back to work

  • You are leaving your baby with a sitter while you are out 

  • Your breasts sometimes feel too full and uncomfortable 

  • You want to have a store of breastmilk in the freezer for emergencies

  • You are trying to increase your milk supply, relactate or induce lactation

Some mums who are expressing regularly can quickly get a large amount of breastmilk from each breast. Other mums simply can’t get a lot at one time, and find it easier to express small amounts more frequently (eg up to 30 mL every 1-2 hours). A few mums find it difficult to express, although they have a good supply and their babies are thriving.  

If you’re expressing to build up a stash, then aim to pump or hand express as frequently as you can to get as much as you can.  

If you’re just expressing to leave some milk in the fridge for when you are out, keep reading. 

How much expressed milk should I leave?

If you’ve been searching on how much breastmilk to leave, you may have discovered a calculation for formula-fed babies or something based on a baby's weight. 

These calculations aren't appropriate for expressed breastmilk. Research tells us that breastfed babies between 1 and 6 months of age take an average of 800 mL per day, although some may need less and some more.  

To work out how much expressed breastmilk to leave, use this as a guide. Assume a total of 800 mL per 24 hours. Divide this by the number of times your baby normally feeds in that period to find the average amount per feed. As an example, if your baby has 10 feeds in 24 hours, then 800 mL divided by 10 equals 80 mL per feed.

If you work out that they will be missing 3 feeds while you are away, the total amount of milk you leave will need to be 3 x 80 mL, which is 240 mL. It’s best to put the milk in several smaller containers so that milk is not wasted. The amount of milk your baby wants may vary from day to day. A few extra small amounts of frozen expressed breastmilk (40 to 60 mL) left with your carer will allow for these changes and avoid wasting a full feed.

It helps if your baby's carer is aware of ‘feeding according to need’ (sometimes called ‘demand feeding’). If they are used to formula-fed babies, it may be helpful to explain that an expressed breastmilk feed is often much smaller than a formula feed.

An exclusively breastfed baby from 1 to 6 months drinks an average of 800 mL in a 24-hour period

(The amount may range from < 500 mL to 1000+ mL)

© Australian Breastfeeding Association May 2022

Read more about expressing and storing

Breastfeeding: expressing and storing breastmilk

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