Before-and-after weights for low milk supply concerns

Can I use before-feed and after-feed weights to see how much milk I make?

Weighing a baby before and after breastfeeding can help mothers understand how much milk they are making. Some mothers with a low milk supply say it helps them accept the need to supplement the baby. Since babies take a different amount of milk at each feed, the baby ideally should be weighed before and after every feeding in at least one 24-hour period. Supplementing the baby should continue during this time, with the amount of supplement based on the baby’s hunger signs after breastfeeding. For this method to work, the baby needs to be healthy and strong enough to remove milk effectively from the breast, and the milk supply should be maximized and no longer increasing. Supplements should be appropriate and not too large.

A) Reasons for using before-and-after weights to assess milk supply

This baby did not gain until infant formula supplements were started. Before-and-after weights showed that the baby was taking in about 250 ml (8 oz) of milk per day from the breast and he required roughly 800 ml (27 oz) of infant formula supplements each day.

Before-feed and after-feed weights (before-and-after weights) is one of several ways to assess a mother’s milk supply, and can provide an accurate measurement of how much milk a mother is making if her milk supply is low. Before-and-after weights are not essential but can be useful.

Knowing how much milk a mother makes can help her understand how much milk supplement her baby needs. Some mothers with a low milk supply struggle to understand their baby’s hunger signs. Before-and-after weights can help them see how the baby behaves after taking a certain amount of milk.

Some mothers in our clinic have said that using before-and-after weights to see the low amounts of milk their baby takes from the breast helps them accept the need to supplement the baby.

If the baby is breastfeeding effectively, before-and-after weights can be a more accurate measurement of the mother’s milk supply than expressing as some mothers do not express well (Meier 2016).

B) Using before-and-after weights to measure how much milk a mother makes

To assess milk supply, mothers need to know how much milk they make in one day (24 hours). Babies take different amounts from the breast at each feed, so while a single before-and-after measurement is accurate, it is unlikely to show exactly how much milk a baby takes in over 24 hours (Kent 2006; Matheny 1985).

Ideally, mothers should do the weighing before and after every feed in a 24-hour period. If some feeds are missed, the measurement becomes less accurate.  

It is even more accurate if the weights are done for two 24-hour periods. The days do not need to be consecutive such as Monday and Tuesday. Doing them on a Monday and Thursday, for example, is fine.

Supplementing the baby with milk should continue if the baby is hungry after breastfeeding when mothers are doing before-and-after weighings.

C) Using the results of before-and-after weights

Before-and-after weights give mothers a fairly good measure of their milk supply but this will only give them a rough guide for the amount of supplement a baby needs as there is a wide range of normal daily milk intake. An average baby between one and six months of age, needs roughly 800 millilitres (27 U.S. fluid ounces) to grow well but the reported range is between 525 and 1,300 ml (18-46 oz). 

Healthy babies know how much milk they need. Forcing these babies to take in a set amount of milk is not appropriate. 

Therefore, the amount of supplement should be based on the baby’s hunger signs after breastfeeding and not on how much milk the baby took in when measured by before-and-after weights. This is different when a baby is premature, a sleepy newborn, or sick

1) Example 1: Following the baby’s hunger signs

Before-and-after weights may show that a mother is making about 450 ml (15 oz) of milk each day. It would then be reasonable to expect her 2-month-old baby boy to need around 350 ml (12 oz) of milk supplement but the baby may indicate using hunger signs that he needs 450 ml (15 oz). The baby should be given the latter amount.  

2) Example 2: A very low milk supply 

Before-and-after weights may show that a mother is making about 150 ml (5 oz) of milk each day. This baby would need large amounts of milk supplement (in the range of 650 ml [22 oz]). There is also in increased risk that the baby may refuse to breastfeed and instead accept only the supplements. Mothers should watch carefully for any signs of this behaviour and be prepared to address it. A tube-at-the-breast system may be helpful in preventing breast rejection. 

3) Example 3: Inappropriate supplementing

Before-and-after weights may show that a mother is making about 750 ml (25 oz) of milk each day. Her baby is also receiving 300 ml (10 oz) of milk supplement. It is possible that this is not necessary and the mother should consider reducing or eliminating this.

D) When not to use before-and-after weights for milk supply concerns

Before-and-after weights can show how much milk a mother makes. For this to work:

1) The baby needs to be breastfeeding effectively

The baby needs to be healthy and strong enough to remove milk effectively from the breast.

If the baby remains underfed or sleepy, the baby should be supplemented and growing well before doing before-and-after weights. Underfed babies may be too weak to breastfeed effectively.

2) The baby needs to be able to latch and suck

The baby needs to latch well and suck effectively in order to remove as much milk as possible from the breast.

3) The milk supply should be maximized and no longer increasing.

Milk supply generally increases until a baby is one month of age, so before-and-after weights to see how much a mother can make should not be taken too soon after the baby’s birth.

Mothers may also be taking steps to increase their milk supply. Mothers should not use before-and-after weights to assess milk supply until the milk supply is maximized.  

4) The amount of milk supplement should be appropriate

Milk supplements should be appropriate and not too large. If a baby gets more supplement than needed, the baby will tend to take less milk from the breast, resulting in an underestimate of how much milk the mother is making.

References

Kent JC, Mitoulas LR, Cregan MD, et al. Volume and frequency of breastfeedings and fat content of breast milk throughout the day. Pediatrics. 2006 Mar;117(3):e387-95
 
Matheny RJ, Picciano MF. Assessment of abbreviated techniques for determination of milk volume intake of the human milk-fed infant. J Pediatr Gastroenterol Nutr. 1985 Oct;4(5):808-12
 
Meier PP, Patel AL, Hoban R, et al. Which breast pump for which mother: an evidence-based approach to individualizing breast pump technology. J Perinatol. 2016 Jul;36(7):493-9