The Possible Effects of Giving a Breastmilk Substitute (Formula) When Breastfeeding 

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What is this information about?

This information explains the effects of giving a breastmilk substitute (formula) to a breastfed baby. It will help you make an informed decision about feeding choices. 

It includes advice on: 

• Recognising normal newborn behaviour 

• The role of colostrum in the first days after birth 

• Why parents may consider using formula 

• The potential effects of formula on breastfeeding 

• Things you can do to protect breastfeeding if you give formula top-up to your baby 

Why have I been given this information?

You have received this information because you may be considering supplementing breastfeeding with formula. It is important to understand how this choice may affect your baby and your breastfeeding journey. 

What is Colostrum and why is it important?

Colostrum is the 1st milk you produce.  It comes in small amounts, but is perfectly designed to support your baby and provide protection. Frequent small amounts are usually enough in the first 24-48 hours.

Why does my baby seem unsettled after birth?

Newborns may appear unsettled due to: 

• seeking closeness and comfort 

• wanting to cluster feed, especially at night 

• being fussy as they recover from birth 

An unsettled baby does not always mean they are hungry or need formula. 

Why do some parents choose to give formula?

Some parents give formula for medical reasons if breastfeeding is not possible. Others may choose to supplement due to concerns about milk supply, baby’s weight gain, or personal preference. 

Is formula the same as breastmilk?

No. Formula companies have not been able to replicate the unique benefits of breastmilk. While formula may be necessary in some situations, it does not provide the same protective properties as breastmilk. 

What are the possible effects of giving formula to breastfed baby?

Using formula alongside breastfeeding may: 

• Increase the risk of allergy to cow’s milk protein (CMPA) 

• Reduce milk supply by lowering breastfeeding frequency 

• Lower confidence in milk supply and breastfeeding ability 

• Make breastfeeding more difficult for the baby 

• Alter the baby’s gut bacteria, increasing the risk of infections

Should I continue breastfeeding if I decide to use formula?

Yes. You can continue breastfeeding alongside formula feeding. A single teaspoon of breast milk can contain as many as 3 million germ-killing and immune-building cells, so any breastmilk you can give your baby is beneficial. 

Things you can do to protect breastfeeding if you give formula to your baby:

• Make sure you express before or after giving a supplement. We can support you with this. 

• Breastfeed or express at least 8 times in a 24-hour period, with at least one feed or session at night. Stimulating your milk supply frequently and consistently in the first two weeks is crucial for long-term milk supply.  

• Have lots of skin-to-skin contact with your baby and try a laid-back feeding position. This can be good if you are tired or uncomfortable. 

• Consider using a cup or tube or syringe – ask a midwife or maternity support worker for assistance with this. 

• If using a bottle, make sure you are paced bottle feeding and following baby’s cues during the feed. 

How do I store my colostrum or breastmilk?

Breastmilk can remain at room temperature for 6 hours.  

We can also store it in our postnatal ward milk fridge or freezer. Please ask a maternity staff member to help you with this.  

All expressed breastmilk will need to be labelled with the mother’s name and the date and time the milk was expressed.

Where can I find more information or support?

• Speak to your midwife, health visitor, or lactation consultant for tailored advice.
• Visit the NHS Website for general guidance on infant feeding.
• Contact local breastfeeding support groups for help and reassurance.
• Visit our Padlet for more resources and scan the QR code below to access it