Tommy's PregnancyHub

Formula feeding FAQs

We’ve answered your questions about formula feeding.

Some women have difficulty breastfeeding or are unable to and others may choose not to. Whatever your reasons, you shouldn’t feel, or be made to feel, guilty or pressured about your decision to use formula. Your baby needs you to stay healthy and happy, not stressed or worried about using formula.

Your midwife or health visitor should give you all the information you need to make sure your baby stays well fed and you can formula feed safely. If you have any questions, just ask.

Can I heat bottles in the microwave?

No. Never warm up formula in a microwave. It may heat the feed unevenly and burn your baby’s mouth.

Will adding extra powder make my baby sleep longer?

No. Too much powder can make your baby constipated or dehydrated. Too little powder may not give your baby enough nourishment. It’s best to follow the instructions on the packet.

Is it possible to overfeed a formula-fed baby?

It can be easier to overfeed a bottle-fed baby than a breastfed baby, because it’s harder for bottle-fed babies to control the milk flow. It can also be easier to unintentionally pressure a baby to feed from the bottle than the breast.

Overfeeding can cause:

  • stomach problems such as bad wind, cramps, and frequent, sloppy, foul-smelling poo
  • belching
  • vomiting
  • irritability
  • sleep problems.

Try not to worry too much about this. You can avoid overfeeding your baby by:

  • getting to know the signs that your baby is hungry (instead of when they just want a cuddle)
  • getting to know your baby’s cues that they’ve had enough
  • avoiding trying to make them drink more than they want.

Talk to your health visitor if you have any concerns about how much formula your baby is drinking.

What if I need to make up a feed before going somewhere?

It’s best to make up feeds one at a time as your baby needs them as this helps avoid infection. Sometimes this isn’t possible, and you may need to take a feed out with you (for example, to a nursery).

If you’re using powered formula, prepare the feed at home and cool it for at least 1 hour in the back of the fridge. Take it out of the fridge just before you leave and carry it in a cool bag with an ice pack and use it within 4 hours. If you don’t have an ice pack or access to a fridge you should use the feed within 2 hours.

As a general rule, if made-up formula is stored:

  • in a fridge, use it within 24 hours
  • in a cool bag with an ice pack, use within 4 hours
  • at room temperature, use within 2 hours.

Some women prefer to use ready-to-feed liquid formula when they’re out and about because it’s more convenient. Just remember that your bottles still need to be sterilised and any unused formula should be thrown away if you can’t store it according to the instructions on the carton or bottle.

I think my baby is lactose intolerant. Should I start them on lactose-free formula?

It’s important to see your GP if your baby is having a reaction to formula milk. They may be lactose intolerant but it’s also possible they have a cow’s milk allergy. These problems need to be treated differently, so don’t make any changes to your baby’s diet until they’ve been seen by a doctor.

NHS Choices. Your pregnancy week by week. (Page last reviewed: 22/07/2014. Next review due: 22/07/2016)

First Steps Nutrition Trust (2020) Infant Milks: A simple guide to infant formula, follow-on formula, and other milks

Unicef Baby Friendly Initiative (2019) Responsive Bottle Feeding

Review dates
Reviewed: 09 May 2019 | Next review: 09 May 2022

This content is currently being reviewed by our team. Updated information will be coming soon.