Breast pain caused by expressing too much milk

Am I expressing too much?

Some mothers express more milk than their babies need. They may do it because their babies can’t breastfeed or because their breasts get too full between feeds. They may worry about their milk supply decreasing or they may be preparing to return to work. Expressing stimulates milk production, but some breasts overreact and start producing too much, becoming overfull, heavy, and tender. Mothers who express a lot of milk are also at risk of milk pimples, plugged ducts, mastitis, or abscesses. To avoid these problems, they can decrease the amount of milk they produce by slowly decreasing the expressed amounts. To do this, mothers keep expressing the same number of times each day but decrease the total amount of milk each day by 30 to 60 millilitres (1 to 2 U.S. fluid ounces).

A) Results of expressing too much milk

Some mothers need or want to express. Unlike a baby who will stop breastfeeding when full, if not done properly, expressing can remove ever-larger amounts of milk and overstimulate the breast (hyperlactation). This is more common in mothers who already had a large milk supply before they started expressing.

Mothers who make a lot of milk may have heavy, tender breasts. They are often painfully overfull. Having a smaller storage capacity magnifies these problems.  

These mothers are also at risk of the following:

B) Why mothers express too much milk

A mother may express too much milk:

  • Because her baby is not breastfeeding and she has overstimulated her breasts by expressing large amounts of milk. This may happen when a baby is premature or breastfeeding ineffectively for other reasons.
  • After breastfeeding because she is unnecessarily worried about her milk supply going down.
  • Because her breasts get too full between feeds and she is expressing to keep them comfortable.
  • When preparing to be separated from the baby.

All of these can result in an excessively large milk supply.

C) How to decrease an over-stimulated milk supply

Mothers who wish to decrease the amount of milk they produce and express need to do it slowly in order to avoid problems. 

Mothers need to continue expressing the same number of times each day but express a little less milk each day. It is usually safe to decrease the total amount of expressed milk by 30 to 60 millilitres (1 to 2 U.S. fluid ounces) each 24 hours. During this time, mothers should watch for the problems described above.  

Mothers can combine the decrease in expressed amounts with massage and cold compresses as they would if treating engorgement.

If mothers still have too much milk, they may need to consider decreasing the expressed amounts even more slowly or using even more aggressive ways of decreasing the milk supply but this is not usually needed.

1) Example

The following table shows a pattern a mother could follow if she wanted to stop expressing. It assumes she has been expressing 60 ml (2 oz) five times a day after the baby breastfeeds for a total of 300 ml (10 oz) a day. 

Table: Reducing the Amount of Expressed Milk


Cullinane M, Amir LH, Donath SM, et al. Determinants of mastitis in women in the CASTLE study: a cohort study. BMC Fam Pract. 2015 Dec 16;16:181