Expressing with a large milk supply

How do I express safely and not create an even larger milk supply?

Mothers with a large milk supply can express to store milk, to manage separation from their babies, or to relieve breast tenderness, but if not done safely, it may result in an even larger supply. That can affect the baby’s feeding behaviour and cause breast problems. Mothers should express amounts in keeping with the baby's needs, avoid expressing large amounts, and monitor their breasts' response to expressing. Expressing for breast fullness should be kept to a minimum. Mothers may be increasing their supply if they notice they are very full for the rest of the day after expressing, expressing just to control fullness, regularly increasing the amount expressed, or having breastfeeding problems.

A) Describing over-expressing

Emptying of the breast drives the breast to make more milk. Mothers with an already large milk supply may produce an even larger supply by expressing in addition to breastfeeding.

The ever-larger supply affects the baby’s feeds and behaviours.

Increasing production also increases the risk of breast tenderness. This results in more expressing. Mothers are then caught in a cycle of over-expressing and may increase their risk of major breastfeeding problems.

You may be increasing your milk production by expressing if you notice that you:

  • Breastfeed your baby at each feed and express more than 300 millilitres (10 U.S. fluid ounces) each day.
  • Have very full and tender breasts for the rest of the day after expressing.
  • Express just to control breast fullness and pain.
  • Regularly increase the amount of milk expressed.
  • Have major breastfeeding problems.
  • Have a baby who has trouble latching onto your firm breast.

If this is the case, start decreasing your expressed amounts.

B) Expressing safely to store milk

Some mothers have a remarkable ability to breastfeed and express without problems and none of the suggestions below will be of any importance. Other mothers however, can get into trouble. The only way to identify these two types is trial and error.  

1) How to express

If the baby takes both breasts at each feed, you can express the first breast while the baby is feeding on the second or you can express both at the same time after the baby has finished.

If the baby only takes one breast at each feed, you can express the unused breast during or after the baby’s feed.

Mothers with a large milk supply often find that constant suction pumps are very effective.

2) Start slowly

Emptying of the breast, especially complete emptying, will increase the amount of milk made. For mothers with very active breasts, this happens within a few hours after one thorough expression. Milk production will decrease if the mother does not continue to express but this can take days.

Expressing is generally easy for mothers with a large milk supply. They may be able to express up to 180 ml (6 oz) at one sitting, but this often leaves them full for the rest of the day as the breasts quickly ramp up production.

Start by expressing just 60 ml (2 oz) and see how your breasts feel for the rest of the day. If they are not too full or tender, you can try to express 90 ml (3 oz) the next day.

Some mothers have a large storage capacity and their breasts can handle larger amounts of milk moving through them. Others feel overfull for the rest of the day when expressing as little as 60 ml (2 oz).

3) Split your expression 

You are less likely to increase the amount of milk you make if you split your expression.

For example, if you need 120 ml (4 oz) for one feed while you are away from the baby, express 60 ml (2 oz) in the morning and 60 ml (2 oz) in the evening instead of 120 ml (4 oz) at one time. Expressing in this way is less likely to empty the breast completely and minimizes the risk of making too much milk.

4) Don’t over-express

The larger the amount of milk expressed, the greater the risk of complications. Should you choose to express large amounts, ensure that there is a need to do so and that you are otherwise well.  

5) Be consistent

If you are expressing regularly for amounts over 150 ml (5 oz), you may need to express a similar amount each day to avoid being too full on the days you don’t express.

C) Expressing safely when away from the baby

Regular expressing when separated from the baby is needed to maintain the milk supply, prevent breast problems, and provide milk for the baby's future feeds. Mothers with a large milk supply are often able to express quickly and effectively.

Mothers should express amounts that are in keeping with the baby’s needs or a little more. They should be careful not to over-express.

D) Expressing safely for breast tenderness

If you need to express to relieve breast tenderness, express only enough to allow your breasts to be comfortable. Expressing more may increase the milk supply, compounding the problem. Alternatives to expressing include massage and cold compresses, which are also used to treat breast engorgement.