breastfeeding baby

This article discusses ‘oversupply’ of breast milk and how to reduce your breast milk supply. You have options including donating to a milk bank and milk sharing.

Some mums make very generous amounts of milk, and this can be uncomfortable for them and for their babies. You might suspect breastfeeding over-supply if:

  • your baby gains weight very rapidly,
  • your baby sometimes splutters and gasps during feeds,
  • your baby is in discomfort after feeds and/or
  • your breasts always feel full and you are troubled by frequent leaking.

Some mums with over-supply notice their babies seem to have explosive, frequent stools, often green in colour (though green poo can be normal, and in itself is not a cause for concern). 

If you think your baby’s discomfort, and possibly your own, are related to over-supply, talk about it with a breastfeeding counsellor or your midwife or health visitor. Having a feed observed by one of them is very helpful, too.

"Babies can be fussy and uncomfortable for other reasons, such as difficulty transferring milk or a tongue tie."

Sometimes, babies just take a little while to settle down, as does your milk production.

What can you do?

Over-supply usually settles down in time, but you can take steps to manage it better. If you are currently offering both breasts at each feed, it may be enough to just offer one breast per feed. If this does not work it is possible to reduce your production by block feeding – though this should only be done once you are sure your baby is thriving and growing well over a period of a few weeks. 

Block feeding means using one breast only each time your baby comes to the breast, within a period of three/four/five or even more hours. You don't use your other breast during this time.

The ‘unused breast’ may fill and be uncomfortable during this time. It’s important you’re careful, and watch for blocked ducts or the development of mastitis, and perhaps gently express a little milk to ease the discomfort – don’t express more than you have to, otherwise you will be stimulating more production. 

How does it work?

Block feeding does not mean preventing your baby from taking the milk they want. Your baby stays on one breast for longer than usual, while the other, unused side remains full, sending a ‘message’ to your body to make less milk. 

Block feeding can be effective within a few days, though for some very generous producers, the blocks need to extend to more hours before they really work. 

There are other ways of coping with over supply. Not much research has gone into this aspect of breastfeeding, so these suggestions are based on what some mums have found helpful. You could try:

  • Adjusting the position of your baby, so they cope with the fast flow better (a more upright hold seems to help).
  • Fully expressing both breasts and getting out as much milk as you can. This seems to be effective if done once or twice, and it seems to recalibrate the production.
  • Gently hand expressing a little milk off, before putting your baby on the breast. This reduces the impact of the first let down, which can sometimes be quite strong, and overwhelm a baby.
  • You might also consider donating or sharing your excess milk (see below).

If you would like to explore any of these options, you can call an NCT breastfeeding counsellor on 0300 330 0700 who can help you find out more. 

What is a milk bank?

A milk bank is a service which collects, screens, processes and then dispenses donated breastmilk to vulnerable babies. Donating to a milk bank is a good option if you are experiencing high production or oversupply. There are currently 17 milk banks in maternity units across the UK. Each one is a member of the United Kingdom Association for Milk Banking (UKAMB). This ensures that the donations are collected and stored to the highest standard. 

Who can donate milk to a milk bank?

Any mum with an excess supply of breastmilk is welcome to donate breastmilk. She will, however, first be screened thoroughly for information on her lifestyle, previous medical history and infections. This is necessary as extra care needs to be taken with tiny and sick babies who are extremely vulnerable to the slightest infection or trace of medication in the breast milk.

How is the milk collected?

The milk bank will provide the donor with sterilised collection bottles and labels. After expressing it, the donor will then freeze it. The amount that is donated will be collected and transported to the milk bank, where it will then be processed separately and pasturised to kill any bacteria. Finally, it will be delivered to where it is needed most. 

Who does the milk go to?

One in nine babies is born prematurely or sick and will have to spend time in a special care unit. These babies are very vulnerable to infection. Easier to digest and containing active enzymes that enhance the maturation of an underdeveloped gut, breastmilk is recognised as the optimum food for these vulnerable infants.

If the baby’s mum cannot express her own for any reason (there may be a delay in her starting to produce it, perhaps they are too poorly to breastfeed) then donor breastmilk is the best alternative.

Other beneficiaries of breastmilk could include babies recovering from gut surgery, babies with allergies or babies with unusual gut syndromes making it difficult to absorb normal food.

How do I find a milk bank?

If you would like to become a donor, then you can contact your local milk back. 

Donor milk is a very precious resource, and even the smallest amount will bring benefits to a sick or vulnerable baby. 

What is milk sharing?

This differs from a milk bank as it is a private arrangement between two mums. This can be done between friends, sisters, or people who make contact via groups on the internet that help put women in touch with one another. These associations supply information to help you decide if this is something you would like to become part of.  

There are some risks in milk sharing, which are greatly reduced if you know the person and can judge if (for example) their milk will be free of medication or other substances, and collected hygienically.  If you would like to explore the options, you can call an NCT breastfeeding counsellor who can help you find out more. 

This page was last reviewed in August 2016.

Further information

NCT supports all parents, however they feed their baby. If you have questions, concerns or need support, you can speak to a breastfeeding counsellor by calling our helpline on 0300 330 0700, whether you are exclusively breastfeeding or using formula milk. Breastfeeding counsellors have had extensive training, will listen without judging or criticising and will offer relevant information and suggestions. You can also find more useful articles here.

National Breastfeeding Line (government funded): 0300 100 0212.

NHS information on mastitis.

Best Beginnings - Bump to Breastfeeding DVD Chapter 7 'Overcoming Challenges'. Managing Breastfeeding – dealing with difficult times.

The United Kingdom Association for Milk Banking (UKAMB) provides information on banks in the UK. 

You might find Unicef's document on the benefits of donors useful. 

Read the NICE booklet on Milk Banks

Related articles

breastfeeding baby

Local activities and meetups

Support our campaign for postnatal mental health
Support our campaign for postnatal mental health

Courses & workshops

Baby First Aid

Find out more

Early Days

Find out more

Introducing solid foods

Find out more