Skip to main content

Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Combination feeding - Breast milk and formula

Combination feeding is when you use a combination of breastfeeding and formula milk to feed your baby. This is also called 'mixed feeding'.

The more you breastfeed or express your breastmilk, the more milk you'll produce.

If you begin giving formula to your baby while you are breastfeeding, they'll take less of your breast milk. This means your body will produce less milk.

Exclusive breastfeeding means giving only breast milk and no formula. This helps your breasts produce enough milk for your baby’s needs.

Early introduction of formula milk can cause your milk supply to reduce. It can also increase the risk of your baby being exposed to allergens.

Breastfed newborns who are fed formula during the first 24 hours are 16 times more likely to develop cow-milk protein allergy than those who are exclusively breastfed.

Feeding in early weeks

Try and breastfeed your baby for the first weeks of their life if possible. Breastfeeding in the early weeks is important for building up your breast milk supply.

Before you consider combination feeding, talk to your midwife, PHN or local breastfeeding support group for help and advice.

Challenges of formula feeding

If you plan to combination feed, it may take time for your baby to adjust to feeding from both the bottle and the breast.

It's best to do it gradually to give your body time to reduce the amount of milk it makes. This helps lower your chance of getting uncomfortable swollen breasts or mastitis.

Breastfeeding and bottle-feeding are very different for your baby. Be patient and give your baby plenty of time to learn how to drink from a bottle.

Breast milk supply

When you begin giving formula to your baby, they will take less of your milk. Your body then makes less milk as a result. This may reduce and stop your milk supply earlier than you planned.

By breastfeeding as many times as you can over 24 hours, you will maintain your milk supply. This means you will be able to breastfeed for longer. Even if you are bottle-feeding, try to give your baby your breast or express your breast milk at each feed. This will help regulate your supply.

If you think you're not producing enough breast milk, talk with your midwife, PHN or a breastfeeding specialist. They can discuss ways to increase your breast milk supply.

The importance of breastfeeding


Because formula milk is not as digestible as breast milk, your baby may experience more digestive discomfort and wind. They may also get constipated.

Breastfeeding issues

You may develop sore nipples while combining breastfeeding and bottle-feeding. This is because the type of sucking action needed to breastfeed is different from that needed to bottle-feed.

Your baby also uses different oral muscles for bottle-feeding. This can make breastfeeding more difficult.

Introducing formula can mean your baby feeds less at the breast. As a result, your breasts can become engorged (too full). If this happens, it's important to remove milk by hand expressing or pumping.

When you introduce bottles it is important to pace the feed. This helps your baby control how much milk they drink and how quickly they feed.

Sore nipples

Engorgement while breastfeeding

Expressing breast milk

Things to consider when formula feeding

When considering formula feeding, be aware of the:

Preparing baby formula

How to bottle-feed


It is important to safely prepare your baby's formula feed.

Paced bottle-feeding

When bottle-feeding your baby, it's important to pace the feed. This helps your baby control how much milk they drink and how quickly they feed.

How to pace a bottle feed and watch a video on how to do it

Getting help

Breastfeeding can take time and patience to learn.

You can get support from:

  • public health nurses
  • voluntary support groups
  • lactation consultants

Ask our breastfeeding expert

Find a breastfeeding support group

Page last reviewed: 10 April 2022
Next review due: 10 April 2025