Expressing breast milk: how much and how often should you pump?

Wondering how you express breast milk, when is the best time to do it, how often and how long it ‘keeps’ for? Then read our comprehensive guide to what you should know…

Expressing, or pumping, milk is often a key part of many a new parent’s routine – a way for the baby to get the benefits of breast milk without having to breastfeed directly and for both parents to feel more empowered and in control of their baby’s care. Women use expressed milk for many reasons such as when returning to work and/or being away from their baby for other reasons; to help encourage milk supply; to allow partners or family members to help with feeding and/or to store milk so it is available, as and when, needed. Some women also express milk if, say, their baby is not feeding well and or there are long gaps between feeds which can leave their breasts feeling uncomfortably full or engorged. It can also relieve pressure from a blocked duct or mastitis.¹ Expressing milk can also be a temporary measure - say, if your baby is too small or sick to nurse initially but then go on to breastfeed exclusively when they are strong enough. Whether you’re exclusively pumping, expressing occasionally or combining it with breastfeeding, it can be done using your hands, a manual pump or an electrical breast pump - the pumps are designed to mimic your baby’s sucking action (as a general rule, manual ones tend to be simpler but electric ones are quicker and do most of the work for you).

There are no set expectations or rules around who should express milk and why, but there are helpful guidelines, recommendations and tips that can help if, or when, you do.

How much, and when, should I be pumping?

You can start expressing milk whenever it suits you and best fits into your life – some women start immediately after the birth to encourage their milk supply, others wait a few weeks, even months, often after they have got to grips with breastfeeding first. How much you need to express will depend on your baby’s age, weight and other factors. Pumping breastmilk is something that can, however, sometimes take a bit of time to get the hang of (and be mindful of the fact that having milk from a bottle is also a new skill your baby has to master after learning how to suckle from the breast). Many women find it easier and more manageable initially to use their hands rather than a physical pump. However, as with breastfeeding, the more you do it the easier it gets. Don’t be discouraged if you feel you are not producing enough - milk output varies and does not always reflect supply, and it can commonly be affected by something as simple as:

The time of day. You tend to express more in the early hours of the morning as levels of milk-producing hormones like prolactin are higher overnight. Milk supply is likely to be at its lowest at late afternoon or early evening.
Stress. If you are stressed your ‘let down reflex’ which signals to your body to trigger your milk flow may be negatively affected.²
Dehydration. Breast milk is composed of around 88% water and if you don’t replenish the fluid lost through producing your milk you can quickly become dehydrated³
It is important, however, not to get too hung up on producing the recommended ‘right’ amounts, however, - all babies are different, and they will generally let you know how much they need. Your milk production should also naturally increase to meet their growing demands so while there is no one-size fits all when it comes to pumping breast milk, as a guide here is what you can expect:

New-born stage (0-1 month) – a new baby needs feeding around every 2-3 hours. That is, 8-12 times a day, including at least one overnight feed. On average, you need to pump around 30-60ml for a new born in the first week. At two weeks, your milk supply should start to increase and your baby should be getting up to 500-700ml daily.⁴ Feed your baby as soon as they show signs of being hungry (common signs include licking their lips or sucking on their hands) but be aware their appetite may increase at different times of the day, and even from day to day. Your body will naturally begin to produce more milk as your baby feeds more and/or you express milk more frequently– demand increases supply. If you are expressing more than your baby needs at any one time, you can refrigerate or freeze the leftover milk for use at a later date (see below).

1-3 months – experts suggest around eight-10 feeds a day and pumping 90-120ml of breast milk per feed is a good rule of thumb.⁵ Your baby’s demands grow at this stage and its best to let them feed them when they are hungry. For some babies this will be every hour (possibly more at times) for just a few minutes, others may need longer but with bigger gaps between. Be guided by them.

3-6 months – a baby aged 3-6 months needs on average 750ml of breast milk a day but anything in the range of 570ml to 900ml is deemed ‘normal’. Again, take your cues from your baby.

After 6 months – a six-month old typically needs 500-600ml of breast milk daily often taken in 4-6 feeds. It is likely that you will start to introduce solid food at this stage, and your milk intake will start to decrease as a result.

How often, and how long, should you pump for?

If you are pumping at home to either encourage supply or stockpile milk, try pumping around half an hour or so after your baby’s first morning feed. Your breasts should be naturally fuller earlier on in the day. If you are doing it away from home to replace feeds you are missing it can help to try to keep to some sort of schedule (i.e.. pump at around the same time you would usually feed your baby at home) to keep your milk supply flowing well. Keeping to a consistent routine and feeding plan is usually helpful. Experts generally suggest around 15-20 minutes per pumping session per breast (although for some five minutes per breast may be enough, whilst for others it may be nearer to half an hour) but rather than thinking in terms of a strict time frame it can help to just focus on when your flow of milk comes to a natural stop, and your breasts are emptied. Fully drained breasts make milk faster and the main sign you have emptied them is that they feel softer and lighter. Pumping both breasts at the same time may be more efficient and using a double pump can help to extract milk in about half the time of a single pump. Some mums are also able to pump from one breast whilst the baby is feeding on the other, but this is not for everyone. Ultimately, however, don’t run yourself ragged trying to build up a huge stash of breast milk – being stressed and exhausted can diminish your milk supply.

Tips to support milk supply

Encourage your milk flow by stimulating the ‘let down reflex’ to get the most milk possible from a given pumping session. To help try to:

Relax. Find a spot that is quiet and secluded where you can get comfortable. Research has shown that women who listened to soothing music and relaxation tapes had an increased milk output and mums who looked at images of their new baby produced even more.⁶
Massage. After thoroughly washing your hands, lightly massaging your breasts can help to get them ready for the ‘let down reflex’ (sometimes referred to as the milk ejection reflex) that signals to your body your milk is ready to flow and causing the milk to be pushed out through the nipples.⁷ As you pump, continue to massage both breasts using light circular movements and continue until milk flow slows to a trickle.
Hold your baby close. Either in person or in your mind. Cuddles with your baby skin-to-skin should increase your milk supply. If you are away from home and not able to physically bond with your baby, look at a photo or video of them or close your eyes and imagine they are in your arms. This should also help to encourage your ‘let down’.
Pick the right setting. If you are using an electric pump begin with it on the ‘let down’ setting – shorter faster bursts of suction which are meant to stimulate the initial suckling your baby does. After a few minutes your pump should switch to regular mode. Avoid using it on the highest suction – start low and slow – pumping shouldn’t be uncomfortable and higher suction does not necessarily equate to more milk.
Try power pumping. This is a technique that mimics a baby’s ‘cluster feeding’ and ‘tricks’ your body to increase milk supply by pumping frequently in short bursts (so replicating what babies do when they have shorter, more frequent feeds).⁸ It generally involves an hour long period of pumping, resting, then repeating to signal to the body to produce more milk. This, however, should be a short-term strategy.
Nourish yourself. When you are tending to the needs of a new baby it can be easy to forget your own needs but when breastfeeding and/or expressing breast milk you need to be eating a nutrient-dense diet rich in vitamins and minerals particularly iron, calcium, vitamin D, omega 3 fatty acids and including healthy sources of protein, fibre and carbohydrates.⁹ Experts also recommend you increase your calorie intake by around 330-400 daily.¹⁰ You also need to top up your fluid intake regularly and the advice from the European Food Safety Authority (EFSA) is that women who are breastfeeding or expressing breast milk should be drinking 10-12 glasses of fluid a day.¹¹ Some new mums find taking a postnatal supplement can help provide reassurance that they are getting the key nutrients they need at this time.
Take a break. Stress is known to affect your let down reflex so try to make time around your baby’s routine – however brief - for some de-stressing activities. Taking a short walk or a quiet five or 10 minute tea break when you should help.
Don’t be too hard on yourself. Increasing your milk supply can take time and there may be times when you pump, and nothing comes out but even if that does happen the very action of the pump sends a signal to your brain that more milk is needed and you should produce more milk reserves soon.

How to store and use expressed milk

Most breast pumps come with their own set of storage bottles as part of a ‘starter kit’ so you can pump and store your milk in the same container. Freshly expressed breast milk will keep for around 6 hours without refrigeration. Alternatively, you can store your breast milk in any sterilised container (guidance from the NHS is to sterilise any containers or parts that your milk touches such as pump flanges, bottles cups or spoons after every use¹² ) or special breast milk storage bags and it can be kept:

In the fridge for up to 8 days at 4C or lower (fridge thermometers are available online).
For 2 weeks in the freezer compartment of a fridge.
Up to six months in a freezer. If you are freezing it, label and date it first and store it as soon as possible. Use up the oldest first. Freezing breast milk in small quantities (around 3-4oz) allows for easier thawing. Defrost frozen breast milk slowly in the fridge before giving it to your baby but if you need to use it quickly thaw it by putting it in a container of warm water or running it under warm water. Don’t use a microwave to warm or defrost your milk. Never refreeze breast milk which has been defrosted.
Expressed milk does not need to be warmed up but many babies prefer it at room temperature. The easiest way to do this is to stand it in a jug of warm water. Warm it just enough to take the chill off and shake off onto your wrist to check it is not too warm. Never heat it up in the microwave – it doesn’t need to be hot and doing this can potentially burn your baby’s mouth.

Common pumping challenges and how to overcome them

Q. I am not producing enough milk to express, what can I do?
A. The more skin-to-skin contact you have before or after feeds/expressing milk will help to stimulate oxytocin (the ‘bonding’ or ‘love’ hormone), and can help trigger milk flow. It can also be helpful to focus on breast massage and stimulation. If you can, try to pump more frequently including overnight (even if you are not producing much milk initially); try power pumping for an hour a day and continue expressing for a few minutes even after your milk flow stops - all this should signal to your body to produce more milk. Also, try some relaxation techniques such as listening to soothing music to reduce anxiety as stress is known to lower milk output.

Q. Do I need to pump milk at night?
A. It is important to express your milk at least once between midnight and 6am because levels of the primary milk producing hormone prolactin is higher at night.

Q. My stored breast milk has ‘separated’, does this mean it has gone off?
A. No. Separation is common and is just the fat from the milk rising to the top. Providing you have stored it correctly, just give it a little shake before giving it to your baby. If breast milk has gone off it normally smells sour and rancid, similar to how gone off cow’s milk might smell. If this is the case, it should be thrown away immediately. Fresh breast milk usually has a sweet, vaguely ‘soapy’ smell.

Q. Is it okay to ‘mix feed’ and give my baby infant formula at times and breastfeed or use expressed breast milk at others?
A. Yes, you can. Many experts, however, suggest mixed or combination feeding like this can make breastfeeding and expressing milk potentially more challenging as introducing formula feeds may reduce your milk supply. There is also a small amount of evidence to suggest that babies may not breastfeed as efficiently if they learn to use a different suckling action when using a bottle rather than feeding at the breast.¹³

Q. My nipples are sore and I am finding expressing milk painful. Should I continue?
A. Expressing milk shouldn’t be painful. It could be that the suction on your pump is too strong or your nipple is being irritated by the flange (also known as a breast shield, this is the funnel-shaped part of the pump which fits over the nipple to create a vacuum seal). Getting the right flange size is crucial for effective pumping and to avoid any discomfort or damage to the nipple. If you are breastfeeding and expressing milk it could be that your baby is not properly positioned and attached at your breast and this is causing your nipples to become sore and irritated. If you are finding it uncomfortable and a struggle speak to your GP or midwife.¹⁴ Some experts suggest rubbing a bit of expressed milk over the nipples at the end of feeding or expressing to help lubricate the area.

*If you are worried about any aspect of pumping milk and/or your milk supply talk to your GP or midwife to get their expert advice.