Feeding Your Baby Infant Formula

Feeding Your Baby Infant Formula

HE Code: 
Booklet A5
Publication date: 
January 2011
Revision date: 
1 February 2013
Status: Hard copies currently out of stock.
For use by health professionals in advising parents and caregivers who have decided to partially or completely formula feed a baby. The booklet includes clear instructions on bottle feeding and how to choose an infant formula.

There are many reasons why some mothers don’t breastfeed. If you feel sad and/or disappointed that you are not fully breastfeeding your baby, it is a good idea to discuss your feelings with your midwife, doctor or nurse. If possible, try to maintain some breastfeeding as well as using formula.

Babies up to six months of age who aren’t breastfed must only have formula – other drinks can make them sick. However, babies over six months may also be offered drinks of water from a cup. Your baby will probably start eating some solid foods at around six months but will still need formula.

Choosing Infant Formula

There are many formulas available. There is no evidence that one company’s formula is better than another’s. Changing from a standard formula to a different or more expensive one is not necessary unless your midwife, doctor or nurse specifically recommends it for your baby.

Milks such as follow-on, toddler milk and growing up milk are labelled as being suitable for babies aged six months and over. These milks should never be given to babies under six months old and are not necessary for most babies over six months of age. Use the same infant formula up to 12 months, then switch to standard (dark blue top) cow’s milk.

Cow’s milk formula

Formula made from cow’s milk is usually recommended for healthy babies who are not breast-fed. Before you buy infant formula, talk to your midwife, doctor or nurse about which cow’s milk formula is best for your baby.

Soy-based infant formula

Your doctor may advise using a soy-based infant formula if your baby is allergic to cow’s milk formula or is unable to tolerate it.

However, a large number of babies who are allergic to cow’s milk may also be intolerant to soy. The Ministry of Health recommends that soy-based infant formula be used only where there is a clear medical need for it.

If you have any concerns, ask your midwife, doctor or nurse about alternatives to soy-based infant formula.

Equipment for Formula Feeds

You need:

  • feeding bottles and teats with caps, collars and sealing discs
  • a bottle brush and a teat brush
  • kitchen tongs
  • a jug with measuring marks (for measuring water to add to the powder)
  • sterilising equipment (necessary for the first three months):


  • a large cooking pot (large enough for water to cover everything in it) with a lid,


  • special sterilising solution (or tablets) and a large plastic container with a lid,


  • a steam sterilising unit designed for microwave sterilising or an electric steam steriliser.

If possible, choose bottles and teats that allow air into the bottle. This makes it easier for your baby to suck out the milk.


Bottles with straight sides and wide necks are the easiest to clean.

Glass bottles are easier to clean than plastic but break more easily.

‘Disposable’ bottles have throw-away liners only.


Newborn babies – one hole in the tip of the teat gives a slow flow to encourage strong sucking.

Older babies – more than one hole gives a faster flow.

Formula should drip from the teat at about one drop per second when tipped.

Washing and Sterilising

Newborn babies are at risk of infection so you must wash and sterilise all feeding equipment until your baby is at least three months old (including any items used with breast milk). When the baby is older, thorough washing and rinsing is enough.

Wash your hands thoroughly with soap and water and dry them on a clean cloth or paper towel.

Fill the sink with warm soapy water:

  • use the bottle brush to clean the bottles inside and out
  • use the teat brush to clean the teats inside and out
  • wash any other items used (eg, bottle caps, kitchen tongs, measuring jug)
  • make sure you remove all traces of milk when cleaning the bottles and teats.

Rinse everything well in hot water and leave them to air dry.

Sterilising by boiling or steaming or with chemicals

If sterilising by boiling:

  • fill a large pot with water
  • place all the washed items in the water, ensuring no air is trapped and everything is covered with water
  • put the lid on and heat the water until it comes to a rolling boil
  • turn the stove off and keep the pot covered until you need the items.

When you need to make up a feed, wash and dry your hands thoroughly and use the sterilised tongs to lift items out of the pot. If you remove items before you need them, cover and store them in a clean place – assemble bottles with a teat inside and a lid on.

If sterilising by steam or with chemicals:

  • follow the manufacturer’s instructions when using steam (in an electric ormicrowave steam steriliser) or chemicals (sterilising tablets or solution).

Preparing Formula

Mixing formula

Read the formula labels carefully (including the use-by date) and follow instructions.

Formula is best made up fresh in time for each feed. If you are carrying your baby’s feed out with you, see ‘Feeding your baby away from home’.

  1. Clean and disinfect a surface on which to prepare the feed.
  2. Before you handle sterilised equipment or make formula, thoroughly wash your hands with soap and water and dry them on a clean cloth or paper towel.
  3. For the first three months, all water used for formula should be boiled and cooled on the day you use it. If you are using a jug or kettle to boil water, wait until it switches off; if you are boiling water in a pot on the stove, let the water come to a rolling boil. Cool boiled water in a covered, sterilised container in the fridge. Keep only for 24 hours.
  4. Pour the correct amount of water into the sterilised bottle before adding the powder. (Not all baby bottles have accurate volume lines on them. To check that your bottles do, look for the standard mark EN14350 on the bottle or packaging, or take your bottles to a pharmacy and ask a staff member to check if the bottles are accurate.)
  5. Use the scoop and instructions provided with each tin to measure the formula powder. Level the powder with a clean knife, but don’t pack down the formula. Add the correct number of full, level scoops of powder to the measured water in the clean, sterilised bottle.
  6. Attach the teat and collar to the bottle. Seal the bottle with the cap. Shake or swirl the bottle gently until the formula is mixed thoroughly.
  7. Handle and store the prepared formula with care. Infant formula powder is not sterile. The temperature at which babies like their formula is also a perfect temperature for harmful bugs to grow.
  • Never add more formula powder or less water than recommended. This could make your baby very sick.
  • Never add anything other than formula powder or water into the formula feed.

In cities and towns, you can use water straight from the tap to make formula after your baby is three months old. Run the tap for 10–15 seconds before you collect the water. If you are concerned about water quality, continue to boil and cool water until your baby is six months old.

Bore water and tank water should be boiled until your baby is 18 months old. If you have a bore, check with your local public health unit that your water is low in nitrate. If the nitrate level is high, ask your public health unit for advice.

Formula should be made just before use. If this is not possible, prepared formula may be stored:

  • at room temperature for no more than two hours
  • in the bottom half of the fridge at the back (2–4°C) for no more than four hours.

Warming formula

Formula can be warmed to body temperature for your baby, but never reheat warmed or partly used feeds. Always check the temperature of the formula by shaking the bottle and dripping some of the formula on the inside of your wrist (without touching the teat). Formula that feels just warm on your wrist is safe for your baby.

Formula that is too hot or unevenly heated can cause serious burns to the baby’s mouth and throat.

With any warming method, make up the formula just before warming. When the formula has been warmed,use it within two hours and throw out any unused formula.

Options for warming

Hot water bath. Place the bottle of prepared formula in a container of hot water. Before you feed your baby, shake the bottle thoroughly so that the formula is at the same temperature throughout the bottle. Check the formula’s temperature.

Baby bottle warmers. Most of these devices are electric and warm the formula to a safe temperature within a few minutes. Follow the manufacturer’s instructions for use. Choose a bottle warmer that sounds an alarm when the safe temperature is reached and then automatically switches off. Always shake the bottle once it is warmed and check the formula’s temperature before giving it to your baby.

Some baby bottle warmers use other ways to heat the formula, for example, using a car battery or activating a metal disc in a reusable warmer pouch. Both of these products are safe to use as long as the formula is prepared by mixing the water and powder together just before warming. Once the formula is warm, remove the bottle from the warmer, check the temperature and finish feeding your baby within two hours. Throw away any unused formula.

Microwaves are not recommended for warming formula because they can overheat the formula or heat it unevenly and burn your baby’s mouth and throat. If you do need to use a microwave, follow these steps:

  • Halfway through the heating process, stop the microwave, remove the bottle and shake it thoroughly. Continue the heating process.
  • After heating, let the bottle stand for 2–3 minutes.
  • Shake the bottle again and check the formula’s temperature before giving it to your baby.

Never reheat warmed or used feeds.

How much formula does my baby need?

Age, weight, time of day, activity level and rate of growth can all affect your baby’s formula needs, as can illness. The formula tin will list general guidelines. Babies are usually fed on demand, so learn your baby’s signals. For the first few days, your newborn baby may need to suck but may not drink much.

Most formula-fed newborns will need around 6–8 feeds in 24 hours for the first few weeks. Some may stop a night feed after about six weeks. Gradually increase the quantity (size) of each feed during the day. When your baby is about two months old, there will probably be 3–4 hours between feeds.

Your baby is getting enough formula if he or she:

  • is content and settles for a couple of hours after a feed
  • is gaining weight at a steady rate
  • has six or more very wet nappies every day.

In hot weather or if your baby is unwell, they may need extra feeds.

Feeding your baby

Getting ready

Thoroughly wash and dry your hands.

Prepare the bottle of formula and wash and dry your hands again.

Some sleepy newborns may need waking up to feed. (If you are worried because your baby is sleepy and hard to feed, talk to your midwife, doctor or nurse.)

Sit in a comfortable chair with your elbows, arms and back supported.

Holding your baby

Your baby needs time for sucking, looking at and listening to you and skin- to-skin contact. Holding your baby while you are feeding him or her is an opportunity to give love and cuddles.

  • Hold your baby in the bend of your arm – it may be more comfortable to switch arms mid-feed.
  • Keep your baby nearly upright and the bottle at the correct angle while you feed them – this helps to prevent ear infections caused by the formula flowing into the middle ear.

Do not leave your baby lying with a bottle to suck on – if babies fall asleep with milk in their mouth, the milk can damage their teeth.

Holding the bottle

Hold the bottle:

  • with enough teat in the baby’s mouth to form a tight seal
  • with the teat in the centre of the mouth and over the tongue
  • at an angle so that the formula fills the teat and bottle neck
  • firmly so that the baby can pull against it while sucking.

Winding (burping) lets your baby bring up any air swallowed during feeding. If your baby wants to stop feeding too soon, they may need burping before they can go on feeding.

Feeding your baby away from home

Formula should not be made up in advance because harmful bugs can grow in it.

Before leaving home:

  • measure the correct amount of cooled, boiled water for one feed into a cleaned (and sterilised if the baby is under three months) bottle and firmly screw the lid on
  • put the correct amount of formula powder in a cleaned (and sterilised if the baby is under three months) container
  • prepare an extra bottle of water and enough extra powder (in a second container) to allow for delays.

At feeding time:

  • Mix the water and powder only when your baby requires a feed.
  • If you are travelling by car, stop to feed your baby.
  • When your baby is over six months, he or she may need extra drinks of water on a long trip, especially in summer.

If you are travelling and need to take prepared formula, don’t warm it before you travel. Put the prepared formula in a chilly bin or insulated bag and use it within two hours.

Breastfeeding is the healthiest way to feed your baby. Giving infant formula to a breastfed baby will reduce your milk supply. If you have stopped breastfeeding, it is possible to restart. This may be difficult because your milk supply will naturally reduce once you are not breastfeeding, but it can increase again to meet your baby’s needs.

This resource has been developed to enable health practitioners to provide objective and consistent advice to mothers who have made the decision to either partially or fully feed their baby formula.

For more information

If you need advice and support with breastfeeding or formula feeding, ask for help from:

  • your midwife, doctor or nurse
  • a Well Child nurse or ring Plunketline 0800 933 922 (24 hours)
  • an International Board Certified Lactation Consultant (IBCLC)
  • the La Leche League (breastfeeding advice and support only)
  • a community or private-practice dietitian
  • the Parents Centre.

You can also ask your health practitioner for Eating for Healthy Babies and Toddlers from Birth to 2 Years Old (Code HE1521).

ISBN 978-0-478-41103-4 (print) ISBN 978-0-478-41104-1 (online)