Formula Feeding Your Baby: What You Need to Know

Formula feeding can come with far more questions than you expected. Which formula should you buy? How should you prepare it? How much should your baby drink? And how do you know when they have had enough?

For most babies who are formula fed, first infant formula is the standard formula used from birth and can remain their main formula throughout the first year. Safe preparation matters because powdered infant formula is not sterile. Feeding itself can be responsive, which means watching your baby’s hunger and fullness cues rather than expecting them to finish a particular amount.

There is no need to feel guilty about using formula. Families feed their babies in different ways and for many different reasons. What matters here is knowing how to prepare, store and offer formula safely, and knowing when to ask for individual advice.

What is infant formula?

Infant formula, also called baby formula or formula milk, is usually made from cows’ milk that has been modified to make it suitable for babies.

Formula is available as powder that is mixed with water or as ready-to-feed liquid. Ready-to-feed formula is sterile until it is opened, while powdered formula is not sterile and needs careful preparation.

The NHS recommends first infant formula as the first formula for most formula-fed babies. Unless a midwife, health visitor or GP advises otherwise, it is the only formula your baby needs before they are 12 months old.

You do not need to move automatically to follow-on formula when your baby reaches six months. The NHS states that switching to follow-on formula at six months has no proven benefit, and babies can continue having first infant formula as their main drink until they are one.

Does the brand of formula matter?

The shelves can make formula feeding look complicated. There are different brands, prices and products marketed for particular feeding concerns.

All infant formula sold in the UK has to meet nutritional standards. A higher price does not automatically mean a formula is better for your baby.

For most babies, first infant formula is the appropriate starting point.

Other products include comfort, anti-reflux, lactose-free, hypoallergenic and soya formulas. Some require medical supervision or professional advice and are not suitable simply because a baby seems unsettled after feeds.

If you think your baby’s current formula is causing a problem, speak to your health visitor, midwife or GP before repeatedly changing products. Symptoms such as crying, wind, vomiting, constipation or feeding difficulties can have different causes and are not enough on their own to identify an allergy or intolerance.

What equipment do you need?

Formula feeding requires relatively simple equipment.

You will need bottles, teats, a bottle brush and a method of sterilising feeding equipment. You may also find it helpful to have enough bottles to avoid washing one immediately every time your baby needs another feed.

There is no evidence that one particular bottle or teat is best for every baby. The NHS suggests that simple bottles which are easy to clean and sterilise are a sensible choice.

Check bottles and teats regularly. Damaged, cracked or torn equipment should be replaced.

If you are buying a formula preparation machine, remember that using a machine does not remove the need to follow safe formula preparation guidance. The NHS advises checking that the water delivered by the machine is at least 70°C when it mixes with the powdered formula.

How to prepare powdered formula safely

Good hygiene is particularly important because powdered infant formula can contain bacteria even when a tin or packet is sealed.

The NHS recommends preparing feeds one at a time as your baby needs them.

First wash your hands and clean and disinfect the surface where you will prepare the feed. Make sure the bottle and teat have already been cleaned and sterilised.

Fill the kettle with at least one litre of fresh tap water. Do not use water that has already been boiled. Boil the water, then leave it to cool for no more than 30 minutes so that it remains at least 70°C.

Following the formula manufacturer’s instructions, put the required amount of hot water into the bottle before adding the powder. Use only the scoop supplied with that formula and add the exact number of level scoops specified on the packaging.

The ratio matters. Adding extra powder can contribute to constipation or dehydration, while adding too much water may mean your baby does not receive enough nourishment.

After mixing the feed, cool the closed bottle under cold running water. Test a little formula on the inside of your wrist before feeding. It should feel warm or cool, not hot.

Never heat formula in a microwave. Microwaves can warm milk unevenly and create hot areas that could burn your baby’s mouth.

Throw away any formula left in the bottle after the feed.

Why bottles need to be sterilised

Cleaning removes milk residue and dirt, while sterilising helps protect your baby from infections.

The NHS recommends sterilising bottles, teats and other feeding equipment until your baby is at least 12 months old.

Wash feeding equipment in hot, soapy water as soon as possible after a feed. Use a clean bottle brush that is kept specifically for bottles, then rinse everything in clean, cold running water before sterilising.

You can sterilise equipment using a cold-water sterilising solution, steam steriliser or boiling, provided the equipment is suitable for the method you choose.

A dishwasher can clean bottles and feeding equipment, but the NHS advises that it does not sterilise them.

Follow the manufacturer’s instructions for your steriliser and handle sterilised equipment with clean, dry hands.

How to bottle feed responsively

Formula feeding does not have to revolve around persuading your baby to finish a particular amount.

Responsive bottle feeding means paying attention to your baby’s cues and allowing them some control over the pace and length of the feed.

Hold your baby close in a semi-upright position, supporting their head so that they can breathe and swallow comfortably. Gently brush the teat against their lips and allow them to draw it into their mouth.

Keep the bottle almost horizontal, with only a slight tilt. This allows the milk to flow steadily rather than pouring quickly into your baby’s mouth.

Your baby may pause during the feed or need to burp. Give them time.

If they stop sucking, turn away, push the bottle away or otherwise show that they have had enough, do not force them to continue simply because there is formula left.

Never leave your baby alone with a bottle propped in place or leave them alone in bed with a bottle because of the risk of choking.

How much formula does your baby need?

It is natural to want a precise number, especially when bottle markings make every millilitre visible.

However, babies do not all take exactly the same amount at every feed. Their appetite can vary, and some babies prefer smaller, more frequent feeds.

The NHS advises following your baby’s lead and feeding when they seem hungry rather than worrying if they do not finish a bottle.

Look for hunger cues such as restlessness, sucking fingers or moving their mouth and head as though searching for a feed. Crying can be a later hunger sign.

Your health visitor will monitor your baby’s growth and can help you understand whether their overall intake appears appropriate.

If your baby was premature, has had difficulties gaining weight, has a medical condition or has been given an individual feeding plan, follow the advice of the healthcare professionals caring for them rather than general feeding guidance.

What about ready-to-feed formula?

Ready-to-feed liquid infant formula can be useful when preparing powdered formula safely is difficult, such as during some journeys or days away from home.

Unlike powdered formula, ready-to-feed liquid formula is sterile until opened. It does not need to be mixed with water.

You still need sterilised feeding equipment, and you should follow the storage and use instructions on the packaging carefully once the container has been opened.

Ready-to-feed formula tends to cost more than powdered formula, so some families use it only occasionally while others find the convenience worthwhile.

Can you switch formula brands?

You may wonder about switching if your baby is unsettled, windy, constipated or bringing up milk.

The NHS states that there is no evidence that switching between standard first infant formula brands does good or harm. If you think a particular formula disagrees with your baby, ask your midwife or health visitor for advice.

Try not to move through specialist formulas without professional guidance.

Anti-reflux formula is recommended under medical supervision. Lactose-free and hypoallergenic formulas also have specific uses, and soya formula should only be used on the recommendation or prescription of a health visitor or GP.

Goats’ milk formula is not a suitable alternative for babies with cows’ milk allergy because the proteins are very similar.

If you suspect an allergy or intolerance, a healthcare professional can assess your baby’s symptoms and advise on an appropriate formula if one is needed.

Formula feeding away from home

Feeding away from home can take a little planning because powdered formula is safest when made fresh.

If you need to prepare powdered formula while you are out, follow current NHS guidance for making up feeds safely. Do not rely on bottled water as a routine alternative to tap water, as the NHS notes that bottled water is not sterile and may contain too much sodium or sulphate.

Ready-to-feed liquid formula can be a practical alternative because it does not need to be mixed with water. You will still need clean, sterilised bottles or suitable sterile feeding equipment.

If you are travelling somewhere where safe drinking water may not be available, check current NHS, UK Health Security Agency or local health guidance before you go.

Formula feeding and closeness

A bottle feed can be a lovely opportunity to slow down and be close to your baby, but it does not need to feel picture-perfect.

Sit comfortably and hold your baby near you. Look at them, talk quietly if you want to and give them time to feed.

The NHS suggests that most early bottle feeds are given by parents, partners or main caregivers so babies experience familiar closeness during feeding.

You may also have feeds where you are exhausted and simply concentrating on safely getting through the next bottle. That is normal too.

Responsive feeding is not about creating a perfect routine. It is about noticing your baby’s signals, holding them safely and allowing them to stop when they have had enough.

When to get professional advice

Speak to your midwife, health visitor or GP if you are concerned about how your baby is feeding, the amount they are taking, their weight gain or their wet and dirty nappies.

Ask for advice if your baby repeatedly refuses feeds, regularly appears distressed during feeding, vomits frequently, seems to be in pain, is unusually sleepy or you are otherwise worried about their wellbeing.

If you suspect cows’ milk allergy, lactose intolerance, reflux or another feeding problem, seek professional assessment rather than diagnosing the problem yourself or repeatedly changing formula.

Speak to a health professional before using specialist formulas such as anti-reflux, lactose-free, hypoallergenic or soya formula where NHS guidance recommends professional or medical supervision.

You can also ask your health visitor to show you how to prepare formula and bottle feed safely if you are unsure. Feeding support is not only for breastfeeding parents.

If your baby has difficulty breathing, becomes unresponsive, is choking or appears seriously unwell, seek urgent medical help.