Formula Feeding

If you’re unable to breastfeed your baby, or choose not to, then you’ll need the facts about formula feeding.

Most infant formulas are produced from cow’s milk that’s been specially processed so that it’s suitable for babies, but you can also get formulas made from goat’s milk or soya protein. You can buy formula either as a ready-to-feed liquid, which is sterile, or as a powder, which is not.

Lots of different brands are available, and it can be really confusing because each makes claims about the fantastic health benefits of their products, but in fact there’s no evidence that one company’s milk is better for your baby than any other, whether it’s more expensive or not.

Here are our top tips to help you separate formula fact from formula fiction:

  • Different types of formula milk contain different proteins. The protein present in first stage milks is easier for babies to digest so can be used from birth. Formula milk marketed for ‘hungrier’ babies contains more of a protein that is harder for babies to digest, and can cause constipation.
  • ‘Follow-on’ or ‘Stage Two’ milks are labelled as suitable for babies from six months old, but there’s no evidence that switching to follow-on milk offers any nutritional or health advantages. At six months old, babies start to be weaned on to solid foods anyway, and a balanced diet is a much better way of making sure they get the nutrients they need, than swapping from a ‘Stage One’ to a ‘Stage Two/follow on’ milk.
  • Once they’re a year old, babies can be weaned onto full fat cow’s milk.
  • Many other types of formula are available. Some are marketed as being helpful for an unsettled baby and some are designed for specific medical conditions. It’s always best to get advice from a healthcare professional before you switch to a different type of formula.

Safe preparation

Infant formula powder isn’t sterile and can potentially contain harmful bacteria, which your baby’s developing immune system isn’t ready to handle. It’s vital that you prepare the formula correctly, follow good hygiene, and wash and sterilise all the equipment you use. Harmful bacteria will only be killed when the temperature of the water reaches at least 70°C.

Follow this NHS Choices step-by-step guide to preparing a powdered formula feed.

If you’re tempted to buy a formula preparation machine, make sure you follow the manufacturer’s instructions to the letter, as there hasn’t yet been much research into their safety.

Formula feeding on the go

If you’re not going to be at home, you’ve got three options when it comes to preparing formula for your baby:

  1. Take a sterilised bottle and a carton of ready-to-feed liquid formula with you – it’s sterile so you don’t have to do anything special to prepare it.
  2. Make up the feed as usual, cool it quickly and store it in the back of the fridge for at least an hour before you go out. You can then transport it in a cool box or bag using frozen ice bricks to keep it cold. You’ll need to use the feed within four hours.
  3. Measure out the formula powder into a small, clean, dry container. Pack a full vacuum flask of just-boiled water and an empty, sterilised feeding bottle. You can then make the feed up as and when you need it.

If you need to warm feeds, use a bottle warmer, or stand the bottle of formula in a container of warm water. Don’t leave a feed warming for more than 15 minutes, and never use a microwave to heat milk as it can lead to hot spots.

If made-up formula is stored in the fridge, you need to use it within 24 hours. The risk of bacteria growing increases the longer it’s stored. If you’re storing it at room temperature, it needs to be used within two hours or thrown away.

The safest option is to make up each feed as and when you need it.

Getting formula feeding up and running

Especially in the early days, bottle-fed babies benefit from skin-to-skin contact just like breastfed babies. It’s a good idea to limit the number of people feeding your baby to enable those close relationships to build:

Your baby will give you clues that they’re hungry. You might see them moving their head and mouth around or sucking on their fingers. As soon as you spot these signs, you can offer a feed. Hold them close in a semi-upright position so you can see their face. Gently rubbing the teat against their top lip will encourage them to open their mouth. Look into their eyes and talk to them as they feed – it will help to reassure them. Your baby will show you when they need a break, and you can gently remove the teat or bring the bottle downward to cut off the flow of milk. It’s a good idea to switch sides each time you feed, to make sure it’s not just one side of your baby’s head that’s always put under pressure.

Teats for baby bottles come in lots of different shapes and sizes, and there’s nothing to say that one type is better than another, so try different ones to see which one your baby likes best. The size of the hole in the teat affects how fast the milk flows. At the start, the milk should drop out of an upturned bottle at one drop per second.

Don’t force your baby to finish a feed – they’ll know when they’ve had enough. The amount suggested on the tin is only a guide!

Giving your baby lots of milk in one feed doesn’t mean they can last longer until their next feed – it’s just as likely to make them sick or cause them to put on too much weight.

You’ll know your baby’s getting enough milk if they’re gaining weight and producing lots of wet and dirty nappies. By the end of the first week, your baby’s poo should be yellowish and have the consistency of mashed potato. As babies get older, they poo less often. As long as the poo is soft, they’re not constipated. If you do think they’re a bit constipated, look closely at the way the formula is made up or the type of formula you’re using. Talk to your public health nurse (health visitor) for more advice.

Useful links


ChatHealth logo

Leicestershire Partnership NHS Trust runs a confidential secure text messaging service for parents of children aged 0-19 years called Chat Health. The service operates Monday to Friday between 9am and 5pm, excluding bank holidays. All texts will be responded to by a public health nurse (health visitor/school nurse) within 24 hours. Outside of the service working hours, you’ll receive a message back to inform you that your text will be responded to once the line reopens.

Should you require urgent health advice in the meantime, please contact your GP, visit an NHS walk-in centre or call NHS 111. For emergencies, dial 999 or visit A&E.

Leicester City: text 07520 615381

Leicestershire & Rutland: text 07520 615382

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