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.