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Supplementing breastfeeding with formula

0-18 months

Breastfed babies are sometimes given extra feeds – supplementary feeds – as well as breastmilk. Here’s what you need to know about supplementing breastfeeding with formula.

About supplementing breastfeeding with formula

Breastfeeding has many benefits – especially for babies, but also for their mums.

But there might be times when a health professional suggests that your baby needs extra nutrition from infant formula, as well as your breastmilk. This is called supplementing breastfeeding.

A baby might need extra feeds if she:

  • has a very low birth weight (under 1500 gm)
  • is born very premature (at less than 32 weeks of gestational age)
  • is very ill
  • isn’t gaining weight well.

Sometimes a mother might become ill – for example, get a severe infection – or might have had previous breast surgery or can’t breastfeed for a few days.

Worried about milk supply?

Many new mums worry about their milk supply, especially if their baby cries after feeds or their breasts feel empty.

The best way to know if your baby is getting enough milk is to check his nappies and weight gains. Your baby is getting enough milk if he:

  • has at least 6-8 wet cloth nappies or 5 very wet disposables in 24 hours
  • has bowel motions every day (if he’s younger than 6-8 weeks old)
  • is gaining weight well (your child and family health nurse will let you know).
If you think your baby might need extra feeds, or if you or your baby is too unwell to breastfeed, talk to your midwife, child and family health nurse, lactation consultant or GP. You can also call the National Breastfeeding Helpline on 1800 686 268.

Before supplementing breastfeeding

There are several things to think about before supplementing breastfeeding.

Regular supplementary feeding might make it more difficult to keep breastfeeding because it can interfere with keeping up a good supply of breastmilk. So if you’re thinking about supplementing breastfeeding with formula, it’s important to talk about it first with your midwife, child and family health nurse, lactation consultant or GP.

You might talk about how to boost your milk supply or how much formula to give your baby, how many times a day to give it, and for how many days.

When supplementing breastfeeding

There are some things to be aware of when you’re supplementing breastfeeding with formula.

When your baby has a feed from a bottle of formula and not from your breast, you might notice:

  • your breasts getting overfull, which can be painful and can cause your body to stop producing milk
  • a reduction in your milk supply
  • your baby preferring the bottle to the breast and then refusing the breast
  • a change in the colour, smell and consistency of your baby’s poos.

Increasing breastfeeding while supplementing

If you’re thinking about reducing the amount of supplementary feeding your baby has and increasing breastfeeding again, talk with your midwife, child and family health nurse and/or lactation consultant.

How quickly you can cut back on supplementary feeding depends on why you’re supplementing, how old your baby is and how much formula your baby is having.

Generally, you can cut down formula by a small amount – for example, 30 ml – each day and replace the formula with more frequent breastfeeds (aiming for 8-12 breastfeeds in a 24-hour period depending on you and your baby).

If your baby can’t always feed directly from your breast, you can feed her expressed breastmilk. This will keep up your milk supply and make sure baby gets the benefits of breastmilk.

Low milk supply

If you’re concerned about your milk supply, see your midwife, child and family health nurse or lactation consultant, who might recommend some of the following strategies:

  • Give your baby breastfeeds more often. Try fitting in some extra breastfeeds each day.
  • Try giving a larger supplement just once or twice a day, just before you want the longest break/s, such as at night, rather than small amounts after every feed. Then breastfeed frequently at other times to boost your milk supply.
  • Try a pattern of breastfeeding from both sides, have a break, then offer another breastfeed. If baby still wants more at this stage, offer a supplement.
  • Let your baby finish the first breast before switching to the second breast. Some babies might take up to 20 minutes or longer to drain a breast and get all the calorie-rich milk. Let your baby decide the length of the breastfeed.
  • Try ‘switch-feeding’, which is switching breasts during the feed. Feed your baby from the first breast while he’s sucking well. When he slows, take him off, burp him and then switch him to the other breast. Keep switching for as long as your baby will suck. This is a way of getting him to drink the most milk in the shortest time.
  • If your milk supply is low and baby is hungry and impatient, offer a small amount of formula first to take the edge off your baby’s hunger. Follow this with your breast. Depending on your supply, you might need to offer more formula afterwards.

The more milk you take from your breasts, the more milk your body will make to replace it.

If you think you have serious low supply, see your midwife, child and family health nurse or lactation consultant, who might recommend using an at-the-breast breastfeeding supplementer device. This device lets baby get extra milk at the breast rather than from a bottle. This device is also useful for babies who are starting to prefer the bottle and refusing the breast.


Common breastfeeding questions: enough milk, too much milk, expressing


This video answers common questions about breastfeeding and milk supply. A lactation consultant says most mums can make plenty of milk for their baby. She talks about typical weight gain, and how to know whether your baby is getting enough milk. She talks about changes in the amount of milk you produce in the weeks after birth and whether you need to express milk.

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Raising Children Network is supported by the Australian Government. Member organisations are the Parenting Research Centre and the Murdoch Childrens Research Institute with The Royal Children’s Hospital Centre for Community Child Health.

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