Typical amounts of expressed milk

How much milk should I get when I express?

Knowing how much milk a mother expresses can provide important information about how much milk she makes and about the effectiveness of expressing and breastfeeding. The amount depends on many factors, including the age of the baby, how well the baby breastfeeds, the milk supply, the length of time between expressing, the time of day, and how well the mother expresses. Some mothers who have a large milk supply will express more than the expected amounts. Occasionally expressing very large amounts can result in an ever larger milk supply and such mothers may need to reduce the amount. Mothers who express less than expected, may need to try a different technique. The amount of milk expressed right after breastfeeding is called the residual volume and is usually 15 to 30 millilitres (1/2 to 1 U.S. fluid ounce) from each breast.

A) Knowing the amount is important

The amount of milk expressed is important. It can provide information about how much milk a mother makes and about the effectiveness of breastfeeding and expressing.

Mothers who express exclusively or frequently may find it useful to keep track of the amount expressed over 24 hours. It can signal a decrease in milk supply. Some mothers use paper charts to record this and others use an app.

B) Typical amounts of expressed milk

The following table shows the average amounts of milk a baby needs to grow well. These change with the age of the baby.  Effective expressing should produce similar amounts. 

Table: Average Expected Amount of Expressed Milk per Day and per Hour Based on the Age of the Baby

Milk is made at similar rates day and night, so that if a mother makes 800 millilitres (27 U.S. fluid ounces) a day, she would make about 30 ml (1 oz) an hour. If she has not pumped for three hours, she could expect to express about 100 ml (3 oz) in total or about 50 ml (1 1/2 oz) from each breast.

The longer the break between expressing, the more milk a mother can expect at the next session. However, long breaks should be avoided because the breasts will become overfull, possibly leading to a decreased milk supply and other problems.

D) Expressing more than expected

If a mother expresses somewhat more milk than described above, that’s great. However, some mothers express extremely large amounts that are well above a baby’s needs and this can lead to problems. Unless they are feeding more than one baby, they may need to reduce the amount slightly. For example, the upper limit of normal milk production between one and six months has been reported as 1,360 ml (46 oz).

E) Expressing less than expected

It is common for one breast, usually the right one, to make slightly more milk than the other. This difference may be exaggerated by expressing. As long as you have enough milk overall, there is no problem. Just treat the two breasts equally and keep breastfeeding or expressing.

Many mothers worry that if they don’t express much they do not have enough milk. Some mothers don’t express well. Having breasts that feel full after expressing usually means that expressing is not effective. They may benefit from trying a different technique.

If the baby is breastfeeding effectively, the milk supply is best assessed by reviewing the baby rather than measuring the amount of expressed milk.

Some mothers truly do not have enough milk and their expressed amounts will be low.

F) Expressed amounts of milk after the baby has breastfed

The amount of milk expressed right after the baby has breastfed is called the residual volume.

1) Residual volumes of 15 ml (1/2 oz) or less from each breast 

Residual volumes of 15 ml (1/2 oz) or less from each breast happen if the mother:

  • Has a full milk supply and the baby is getting enough milk from the breast.
  • Does not express effectively.
  • Has a temporarily reduced milk supply.
  • Has a low milk supply.

If the baby has breastfed well, the residual volume is often 15 ml (1/2 oz) from each breast (Dewey 1991). The baby does not totally empty the breast.

Healthy mothers generally have a higher residual volume in the morning after a nighttime break and may find this is often a good time to express in order to store milk for later use.

Mothers with a low milk supply will wonder why the baby leaves milk behind in the breast yet needs to be supplemented. Consider two glasses of milk – one full and one half-full. After each glass is emptied, both glasses will have a little bit of milk in the bottom of the glass. Similarly, breastfeeding mothers will also have a little bit of milk left in their breasts, regardless of how much was there at the start of the feed.

Thorough emptying of the breast by expressing after breastfeeding can increase the amount of milk expressed if the breast can respond to this stimulation. However, not all breasts are able to do so.

2) Residual volumes of more than 15 ml (1/2 oz)

If a mother generally obtains significantly more than 15 ml (1/2 oz) of milk when she expresses after breastfeeding, the mother may: 

  • Have a full milk supply and the baby is getting enough milk from the breast.
  • Have a large milk supply from the time of the baby’s birth.
  • Have created a large milk supply by expressing.
  • Be over-supplementing.

It is also possible that the baby may:  

References

Dewey KG, Heinig MJ, Nommsen LA, et al. Maternal versus infant factors related to breast milk intake and residual milk volume: the DARLING study. Pediatrics. 1991 Jun;87(6):829-37