How much breast milk does your baby need to thrive?

Full breast milk production is usually reached by about two weeks after the birth

Most women reach full milk production by about two weeks after the birth. Within the first two weeks a woman's supply builds to an average of over 600 mls taken by the baby from both breasts in a 24-hour period.

Then, in women who are successfully and exclusively breastfeeding, milk volume is pretty much stable from when the baby is one month old to six months of age, at about 800 mls in a 24-hour period. Some happy thriving babies are drinking just 700 mls from their mother's breasts in a 24-hour period.

From about six months of age, as solids are introduced, milk production naturally begins to drop off.

Total milk volumes are highly variable between women who are exclusively breastfeeding babies with good weight gains

Normal is a very diverse condition in humans. The daily volume of milk produced by a mother who is exclusively breastfeeding and whose baby is gaining weight well is consistent for each mother-baby pair, but highly variable between pairs.

• In the research, it's estimated that 600 mls in a 24-hour period is the lower end of milk volumes required to meet a baby's needs as he exclusively breastfeeds with good weight gains. But some exclusively breastfed babies are taking 1350 mls from their mothers' breasts within a 24-hour period. Mothers breastfeeding multiples may produce about two litres of milk in a 24-hour period!

• The amount of milk transferred in each feed is also highly variable in successfully breastfeeding women. Some breastfeeds don't really transfer milk at all - this is normal. Some women transfer 75 mls from a full breast, others up to 380 mls. But these figures from the research about breast storage capacity don't really help us much in the real world. For a start, if we are consistently letting our breasts run full, we are dialling down our supply. The breast can store milk above what is likely to be removed in any feed, but milk storage capacity is dynamic, shaped by feeding patterns as well as by genetic predisposition.

• Health professionals calculate how much milk your baby needs in a 24-hour period using the calculation of 150 mls/kilogram of your baby's weight. This is, however, very approximate once you consider just how variable infant milk needs are.

If you offer a pattern of frequent, flexible breastfeeds over a 24-hour period, your baby has his best chance of taking and generating the milk he needs. (This is true for most, but is also not true for some mother-baby pairs. You can find the causes of low supply here.)

When we're offering frequent flexible breastfeeds, our breasts may never feel tight and full. From about six weeks after the birth, your breasts mostly won't feel full the way they did in the early days of breastfeeding. This is a good thing, not a sign of low supply!

There are two vital aspects to maintaining a milk supply which meets your baby's caloric needs. These are

1. Good fit between your and your baby's body, which eliminates breast tissue drag and ensures pain-free, efficient milk transfer. You can find out about fit and hold starting here.

2. Frequent, flexible breastfeeds. You can find out about frequent flexible breastfeeds starting here.

Selected references

Hartmann PE, Atwood CS, Cox DB, Daly SEJ. Endocrine and autocrine strategies for the control of lactation in women and sows. In: Press P, editor. Intercellular signalling in the mammary gland. New York1995.

Rios-Leyvraz M, Yao Q. The volume of breast milk intake in infants and young children: a systematic review and meta-analysis. Breastfeeding Medicine. 2023;18(3):188-197.