Measuring breast milk intake of premature babies

How do I know if my premature baby is breastfeeding well?

It is sometimes hard to tell whether premature babies taken in enough milk by breastfeeding. They may be too weak to communicate their hunger and are often sleepy during and after breastfeeding. Sometimes they look as if they are breastfeeding effectively when they are not. It is critical to their growth and survival to take in enough milk, so health-care providers monitor them closely. Premature babies who are breastfeeding well latch easily and stay latched for most of the feed. They may choke, gulp and breathe quickly at the start and suck well during the feed. As babies start taking in more milk, they may ask for less or no milk supplement and mothers may notice a decrease in the amount they express. Weighing the baby before and after feeds is another way to figure out how much milk the baby is getting. It also allows mothers to see which of their baby’s breastfeeding behaviours result in good milk intake.

A) Importance of knowing the premature baby’s milk intake

Full-term babies have a number of ways of letting their mothers know they are getting enough milk and growing well. They breastfeed normally. After feeds, they are happy and do not show any hunger signs. If they don’t get enough milk, they show clear signs of poor growth and hunger.

In contrast, premature babies who are trying to breastfeed may:

  • Be too weak to communicate that they are hungry.
  • Sleep a lot.
  • Have trouble taking in milk from the breast.
  • Look as if they are breastfeeding effectively but are not.
  • Have mothers with a low or a reduced milk supply because of their reliance on expressing and other challenges.

Also, if they are underfed, they become even sleepier, leaving them even less able to communicate their hunger. This can start a dangerous cycle of sleeping and underfeeding.

Premature babies have less fat than full-term babies and are less able to cope with not getting enough milk. It is critical to their growth and survival to take in enough milk. For this reason, health-care providers closely monitor premature babies and may need to know exactly how much milk they take in.

B) Signs of milk intake while breastfeeding

Premature babies who breastfeed effectively have normal feeds and show signs of taking in milk.

1) Effective breastfeeding

Premature babies who breastfeed well will:

2) Signs of taking in milk

Premature babies who are taking in milk show some of the following signs:

  • Choke at the start of the feed.
  • Gulp at the start of the feed.
  • Breathe more quickly at the start of the feed.
  • Make ahh-ahh-ahh or caw-caw-caw noises during the feed.
  • Clicking during feeds.
  • Have tummy cramps during or right after the feed.
  • Show no hunger signs after breastfeeding.
  • Soften the breast by breastfeeding.

They will also gain well and fill in

C) Sucking rate

Another way to see if a baby is getting milk while breastfeeding is to watch how quickly the baby sucks.

When babies suck but don’t get any milk (non-nutritive sucking), the jaw moves up and down a little more quickly, about 90 sucks a minute compared with 75 for effective, regular breastfeeding (Sakalidis 2013). 

The jaw movement may also appear a little different. Instead of slower, steady draws by the jaw, the jaw moves in more of a quicker, chomping action.

Sucking rates can also be too slow. A baby who consistently has a very slow, sleepy suck will not take in much milk.

D) Less expressed milk

Mothers who express after breastfeeding a premature baby tend to express predictable amounts. When babies start taking in more milk from the breast, mothers notice they express less milk after the baby has breastfed well than after a poor feed or before a feed.

It is also possible for the amount of expressed milk to go down if mothers are not expressing effectively. This should be addressed.

E) Less milk supplement

As babies become more effective at the breast, babies may ask for less and less milk supplement or not be hungry at all after breastfeeding while growing well.

F) Before-feed and after-feed weights

Before-feed and after-feed weights are useful to assess breastfeeding by premature babies. They can be used to:

  • See how much milk the baby is taking in.
  • Test the effectiveness of a nipple shield.
  • See which size of nipple shield is more effective.
  • Allow mothers to see what breastfeeding behaviours are more successful in getting milk.

Before-feed and after-feed weights need to be done carefully because premature babies take in relatively little milk. They are not helpful if the baby is breastfeeding very poorly or is healthy and growing well without milk supplements.

Once a baby is breastfeeding well but still needs milk supplements, before-feed and after-feed weights can be used to:


Sakalidis VS, Williams TM, Garbin CP, et al. Ultrasound imaging of infant sucking dynamics during the establishment of lactation. J Hum Lact. 2013 May;29(2):205-13