Expressing breastmilk: how to do it, when to do it and how to store it safely

to provide breastmilk for someone else, such as your partner, to feed to your baby
to introduce your baby to the experience of drinking breastmilk from a bottle (again allowing you to share feeding duties with others)
to continue breastfeeding if you can't be with your baby at every feed time
to give your baby breastmilk if they're born prematurely, are in hospital or are having problems breastfeeding
to relief discomfort if your breasts are engorged and painful
to ensure your milk supply is maintained if you’re away from your baby during the day
to boost your milk supply

If you're thinking of expressing breastmilk, you'll need to know when you can start, what you'll need, how and when to pump, how long it will take – and how to store the milk you've expressed. We've got all the answers here...

When can I start to express milk?

In theory, you can start expressing whenever you want, although, if your baby is well and at home with you, your midwife or health visitor may suggest you wait till about 4 weeks after the birth – to give you (and your baby) a chance to get used to breastfeeding and to give you time to get your milk supply time well established.

In the first 4 weeks, you and your baby work together to initiate and build your milk supply. If your baby is healthy and breastfeeding is going well, you won’t need a pump to help with this. Pumping is, however, really helpful – now or later – if you need to be apart from your baby any time
Dr Danielle Prime, lactation researcher

The exception to this is if your baby requires hospitalisation from birth – either because they've been born prematurely or for other health reasons – and it's not practical for you to breastfeed (from your breast) at first.

In this case, research shows that starting to express breastmilk as soon as possible after your baby's born – and continuing to do so regularly –can help get your milk supply going¹ so that you're better able to breastfeed when your baby's well enough to latch onto your breast.

And actually, even if you don't intend to breastfeed later, expressing some breastmilk for your baby just while they're in hospital can help to boost their growth and bolster their immune system². The hospital staff should help you get started with expressing and guide you through the whole process.

What will I need before I start expressing milk?

You can hand-express (see How do I express by hand, below?), which can be useful in the very early days if your baby's in hospital and also for relieving uncomfortably full breasts. If you're hand expressing and want to keep the milk you're expressing, you'll need a (sterilised) wide-mouthed container to collect your milk in and some sterile storage bags or lidded bottles to store your milk in.

If you're expressing at home once your milk supply is well established, you'll probably find it easier – and quicker – to use a breast pump, either a manual one, an electric one or one that can be used both ways.

Which are the best breast pumps? See which ones our testers and reviewers rated most highly

In addition to the pump, you'll need sterilising equipment to prepare your pump and container bottles, and sterile storage bags to store your milk in.

Can I express to increase my milk supply?

If your breastfeeding baby is gaining weight well, you probably don't need to be worried about your milk supply. But if you do think you're not producing enough milk, then yes, expressing can help to increase your milk supply.

"Frequently and effectively removing milk from the breast helps signal to the breast that more milk is needed, and also helps increase the production of milk," says Danielle.

"This is the basic principle of 'supply and demand'.

"So, if you are breastfeeding and trying to build your milk supply, additional pumping is recommended: pump at your maximum comfortable vacuum, and double pump (pump each breast at each session) if you can."

Make sure you're breastfeeding or expressing a total of 8 to 12 times every 24 hours. You may find it easier to add in an expressing session in the evening or early morning or to express after every breastfeeding sesseion.

However you decide to do it, "avoid waiting long intervals for your breasts to feel very full before pumping," says Danielle. "Frequency here is the key."

If you unsure whether you're making enough milk for your breastfeeding baby, it's a good idea to talk to your GP or health visitor or to consult a lactation counsellor.

Which is better: a manual breast pump or an electric one?

It's really a matter of personal preference

With a manual breast pump, you are the source of power, so you'll need to activate the suction by squeezing and releasing a handle.

Pros: Much cheaper; smaller, quieter and generally more portable and discreet
Cons: Can be fiddlier to operate at first

With a an electric breast pump, the batteries (or mains connection) are the source of power and you programme the pump to control both the strength and speed of suction for you.

Pros: Generally pumps milk quicker and more efficiently (some 'dual' models will pump from both breasts at the same time – good if you need to greatly increase your milk production); often possible to hire rather than buy
Cons: Expensive; bulkier; noisier; requires charging (or mains supply)

How do I express breastmilk properly with a breast pump?

It has to be said that expressing milk with a breast pump is not one of the most instinctive – or dignified – things parents do! It may take you a few goes to get the knack and get used to handling the breast pump and all its accompanying bits and pieces.

Here are Danielle's tips for easy expressing:

Wash your hands before you start pumping (and sterilise your breast pump between each use)
Make sure you’re sitting straight but comfortably. The more relaxed you are, the more easily your milk should flow
Ease your breast and nipple into the pump funnel, rather than forcing it, and support your breast underneath with your hand
Hold the breast pump gently on your breast. Pressing too hard could compress your breast tissue and obstruct milk flow
Make sure your nipple is in the centre of the funnel
Don’t expect the milk to flow straight away. It can take several pumps for suction to establish and some more after that to get your milk flowing
Pump from each breast twice: once the milk flow starts to decrease on 1 side, switch to the other

"For your 1st breast-pumping session," says Danielle, "express for around 15 to 20 minutes. Don't worry if you don't collect much milk at first: regular extra suction should soon stimulate your breasts to produce more milk."

How high should you set the suction on an electric pump?

"Start off gently," says Danielle. "But once your milk is flowing, you should always pump at the highest vacuum setting you can use while remaining comfortable. In research, this was found to remove a similar amount of milk as a baby does during breastfeeding.

"To find the right level for you, increase the breast-pump suction gradually until it becomes slightly uncomfortable, and then turn it down a notch."

How do I hand-express breastmilk?

"Hand expression is what they teach you if your newborn baby is kept in hospital," says Danielle. "It's a good way to get your milk supply going when your baby's too ill to breastfeed. But it's also a very useful way to relieve your breasts if they feel uncomfortably full, which they can when your milk 'comes in', for example.

"You can also hand-express before you breastfeed, if your let-down reflex is a bit slow: hand-expressing can stimulate let-down."

If your baby is in hospital, the nurses will show you how to hand-express. But here's a basic guide to what to do:

Wash your hands

Gently massage your breasts or cover them with a warm flannel, to encourage your milk 'let down' reflex

Cup your breast with one hand, and make a C-shape around your breast with the fingers and thumb of your other hand

Squeeze towards your areola, with the C-shape hand, keeping your fingers and thumb just outside your areola (don't squeeze your actual nipple as this could make it sore)

Release the finger pressure and repeat. Try to get into a rhythm – but don't let your fingers slide, rather than squeeze

Drops of milk should start to appear and then milk flow more quickly. When the flow slows down, move your fingers around to a different part of your breast and start the squeezing process again

We think the beginning of this Australian video (from the private Epworth Health Centre in Victoria) has some great graphics that show you very clearly how to hand express.

I'm not getting much milk out when I express. How can I pump more breastmilk?

You will get better at pumping – and 'more productive' – the more you do it. But it's quite normal, particularly at first, not to be able to produce large quantities of milk. After all, however fondly you regard it, putting your breast pump to your breast is never going to provide the same emotional trigger that gets your milk flowing as putting your baby to your breast.

"Many advanced breast pumps now try to mimic the way your baby feeds but they won’t be able to stimulate the same feelings in you as your baby does," says Danielle. "But there are a few things you can do to get the most out of expressing...

Try to relax. Make a conscious effort, before you begin, to shake the tension out of your shoulders, take a deep breath and put your mind at ease. It can help not to think about the milk you're aiming to express; instead, have some music playing or watch something on TV.
Express while you feed. It can take a bit of co-ordinating but it's worth it. "Especially when you're first starting out with pumping, expressing on one breast while your baby feeds on the other can be very effective," says Danielle. "That's because, when your baby triggers your let down, both breasts will respond with milk flow (this is why some mothers experience leaking or dripping on the other breast when feeding)."
Try double pumping. "If you’re planning to pump regularly, it’s well worth double pumping," says Danielle. "Expressing both breasts at the same time results in more milk being expressed. In fact, when I conducted a study to try to understand why, I found that when women double pump, they have an additional let-down in each pumping session. This means they typically express almost a fifth more milk, and milk with a higher fat content too. This can really add up: after just a few pumping sessions you could have an extra bottle."
Express with your baby nearby – or with 'baby props'. If you're not expressing while you feed, then having your baby nearby and looking at them as you 'latch on' the breast pump can help with your let-down while you express. If that's not practical, try looking at a picture of your baby on your phone or even sniffing one of their babygrows – anything that makes you feel all warm and fuzzy about your baby.

How long should I express for?

It all depends on your milk-flow pattern, says Danielle. "In my research studies," she says, "it was clear that some mothers need to pump longer than others due to their number of let-downs, which determine how often and how long their milk flows.

"A mother who only has let-downs early in a session will have removed most of her milk within 8 to 10 minutes, and pumping any longer won’t reward her with more milk. Conversely, a mother who has many or late let-downs may need to pump for 15 minutes or longer to drain her breast thoroughly.

"What’s really amazing is that, whatever your own flow pattern is, it will be the same each time you pump and each time you breastfeed. All you need to do is work out what your pattern is.

"To do this, watch while you pump, noting when milk starts to drip into the container, when jets of milk start coming from your nipple and when the jets return to drips again as your milk flow stops. Now you can tailor the length of every pumping session."

How often should I express?

This all comes down to the reason you're expressing: if you're expressing to establish your supply or maybe even to feed your baby exclusively by pumping, then you'll need to express several times a day.

As a rule of thumb, lactation experts at Le Leche League GB say, to establish milk production without breastfeeding your newborn baby, you should be aiming to aim to express 8 to 12 times every 24 hours, including at least once during the night, to mimic a baby’s natural breastfeeding pattern.

If you're expressing to boost your supply, fit your expressing sessions in after or between each breastfeed to stimulate your breasts to make milk faster.

If, however, you're expressing so that you can have an evening out (or an evening 'off', with your partner doing the feeding duties), that's very different: you'll just need to have expressed enough milk to cover the feeds that you'll be away for.

And you don't have to express all of that in one go. Because you can refrigerate and freeze breast milk (see How do I store expressed breastmilk?, below), you can express as and when it's convenient in between feeds (or even while breastfeeding your baby on the other breast) and build up a little store of milk.

What's the best time of day to express?

Some women swear by pumping in the morning; others by doing it in the evening. What's key, says Danielle, is finding an expressing rhythm that really works for you, whatever time of day that is.

When you find times that work for you, stick with them so your body gets used to your breast pump use and the extra demand on your milk supply.

That said, it's interesting to know that there's some evidence that expressing at night produces milk which includes a sleep-inducing substance in it^3.So is expressing at night for a night-time feed good for helping your baby sleep better?

"You may have heard night-time breastmilk is different to daytime breastmilk," says Danielle. "And it is true that breastmilk is higher in some nucleotides at night, and these building blocks of our DNA have a sleep-inducing function.

"While these may help your baby develop healthy wake-sleep patterns, exactly why they are there and how influential they are is still being researched.

"So feel free to try to feed expressed milk at the same time of day as it was expressed but, until we learn more, do not be too concerned if this doesn’t match."

Trouble expressing? Here are Danielle Prime's top tips

Problem: I don't feel like I'm producing enough milk

Solution: "While you don't need to 'train' your body to express milk in the 1st few weeks, it may take you some time to get the hang of using a breast pump, and the key is to be patient, even if you are not able to express as much as you like right away.

Problem: It hurts when I pump

Solution: "Once your milk is flowing, you should always pump at your maximum comfort vacuum, which is the highest breast pump setting you can use while remaining comfortable. To find the right level for you, increase the breast pump suction gradually until it becomes slightly uncomfortable, and then turn it down a notch."

Problem: The milk's not flowing

Solution: Relaxing is key to helping your milk flow. "Put the TV on and sit back and relax!" says Danielle. "It is great to pump in a place where you feel at ease. Being relaxed is essential for the release of the hormone oxytocin, which stimulates your let-down reflex. Discomfort and distractions can hamper this process, so choose somewhere private and comfortable, and make sure your arms and back are well supported as you pump. Some mums find deep breathing, soothing music, visualisation techniques, or having their partner massage their back and shoulders, can help them express more milk."

Mum Sian, a member of our MadeForMums community, reveals her tip for getting the milk to flow: "I never seem to get much milk when I express and I have read that people use warm flannels before to help, so I decided to go 1 step further and use my [manual] pump while I was in the bath and it worked! I kept massaging my boob with a hot sponge and my milk flowed really well. Just though I'd let you know in case anyone else wanted to give it a go."

Though please don't use an electric pump in the bath!

How do I store expressed breast milk? How long can I store breastmilk for?

You should always store breastmilk in a sterilised container, marked clearly with the date. You can store it in a feeding bottle or in special breastmilk storage bags that come with a sealing clip.

How long you can store your milk depends on how your storing it⁴...

Fridge: up to 5 days at 4°C or lower. Store the milk at the back of your fridge, where it's coldest, not in the fridge door. If you're not sure of your fridge temperature or the temperature is above 4°C, use within 3 days, rather than 5
Ice compartment of a fridge: up to 2 weeks
Cool bag with ice packs (if the milk is cooled in fridge first): up to 24 hours
Freezer: up to 6 months at -18°C or lower.

You can add a new batch of breastmilk to the container of breastmilk you're already storing in the fridge but you do need to cool in the fridge it separately first: don't add body-temperature breastmilk to breastmilk that's already chilled.

Do bear in mind that, if you're planning to freeze your breastmilk, you need to leave a couple of centimetres of space at the top of your container or storage bag for the milk to expand into as it freezes.

How do I defrost frozen breastmilk?

It’s best to defrost it slowly in the fridge overnight. If you need it more quickly, though, you could defrost it by putting it in a bowl of warm water or holding it under a running tap of warm water.

Once the milk is thawed, use it straightaway (give it a gentle shake if it's separated into different layers). If it's not used within 2 hours, throw it away. Don’t refreeze breastmilk once it’s thawed.

How do I warm up breastmilk before feeding it to my baby?

Put the milk in a bottle and pop the bottle in a bowl of hot water to warm it through, or run hot water over it. Test the temperature by dropping a little milk onto the inside of your wrist: it should be blood-warm.

Don’t use a microwave to warm breastmilk or heat it in pan of boiling water, as both of these methods can produce hot spots, which may burn your baby’s mouth.

Do I need to sterilise everything?

Yes but not necessarily before every expressing session, although it's very important to make sure everything you use is really clean every time.

"Always wash your hands before and after expressing, and clean any pump parts and bottles that have been in contact with your milk or your baby’s mouth," says Danielle. "Be sure to check your breast-pump instruction manual for any specific cleaning guidelines."

Then, about once a day if you're expressing every day or before you use your pump for the first time or after a while of not using it, you need to sterilise (or, strictly speaking 'sanitise') all the parts of your pump (see Key tips for sterilising your breast pump, below).

"Be sure to allow all the pieces to dry completely after this," says Danielle "and then you can then store the pump set in a clean bag or container until you need to use it again."

Key tips for sterilising or sanitising your breast pump
First, rinse off your pumping equipment with drinking-quality water (not chilled) to remove any milk proteins left behind. 
Then wash all parts with warm water (approximately 30 °C/86 °F) and washing-up liquid. 
Rinse the parts again with drinking-quality water for 15 to 20 seconds. 
Alternatively, you can wash the pump parts in the top rack of your dishwasher using your usual dishwasher detergent. Smaller parts can be placed in the cutlery section. Make sure bottles, breast shields and teats are facing downwards. 
Dry the equipment completely with a clean, dry cloth or leave to air-dry completely on a paper towel or clean tea towel. 

What about expressing at work? What are my rights?

If you want to continue to give your baby breastmilk once you're back at work, this probably means you'll need to express at work – unless you work near enough to wherever your baby is being looked after to go in and feed them in at the right time(s).

If you're planning to express at work, you need to let your employers know as soon as you can – in writing. In the letter, you should ask your employer to make any reasonable adjustments to your working hours or conditions at work to enable you to continue breastfeeding on health and safety grounds.

The law does not require your employer to give you paid breastfeeding breaks but employers are required to protect your health and safety while you are breastfeeding by making reasonable changes to your working conditions or hours of work. This might include allowing you to work shorter shifts, to have extra breaks to express milk or to avoid night work or overnight stays.

You also have the right to ask for flexible work. Any changes to your contract of employment are usually permanent but, in order to accommodate a period of breastfeeding, you and your employer can agree to a temporary change.

Employers should also provide a clean, private space with a locakable door (that's NOT a toilet) for you to do your expressing in. They should also provide somewhere your expressed breastmilk can be safely stored until you can take it home.

You can find more info on your rights at work for breastfeeding mothers at Maternity Action. Or you can download a PDF put together by Maternity Action and the TUC.

Where to get help with expressing

Other good resources:

Face-to-face help:

Talk to your midwife or health visitor
Talk to an IBLCL-certified lactation counsellor

About our expert Dr Danielle K Prime

Danielle studied at the School of Chemistry and Biochemistry at the University of Western Australia, where she graduated with a PhD in 2010. For her thesis, she investigated breast milk removal during breast pumping, which hormones play a role in milk flow and how mothers, nurses and doctors can be better informed about breastfeeding. She now works as a Research Associate at Medela in Switzerland.

References

^{1. Pump Early, Pump Often: A Continuous Quality Improvement Project. Spatz, D et al. The Journal of Perinatal Education Vol 24 Issue DOI: 10.1891/1058-1243.24.3.160
2. Human milk for the premature infant. Underwood, M. Pediatr Clin North Am. 2013 Feb; 60(1): 189–207. Published online 2012 Oct 18. doi: 10.1016/j.pcl.2012.09.008
3. The possible role of human milk nucleotides as sleep inducers. Cristina L. Sánchez et al. Nutritional Neuroscience Volume 12, 2009 Issue 1
4. NHS guidelines on expressing and storing breastmilk}

Pics: Getty / Medela