How to Pump and Store Expressed Milk

Published by 
Jess Miller
Last updated: 
April 4, 2023

Whether you are just starting to pump, are looking for a refresher about breast milk storage guidelines, are getting ready to go back to work, or have a day planned away from your breastfed baby, you know that you are going to need to have expressed milk ready for while you are away, pump for any missed feedings and make sure that you are storing that milk safely.

Here I will go over pumping basics like how often and when to pump, as well as the right way to store and eventually use your milk.  I remember my first day away from N.  I did a day trip to visit my sick grandmother.  All of the pumping and storing leading up to that day, and especially figuring out the logistics of pumping and storing while I was on the road away from her felt really overwhelming!

This article will take out the guess work and teach you everything you need to know about how to pump and store breastmilk.

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Adding Pumping to your Postpartum Routine

As the time to go back to work draws closer, or in the week leading up to your first full day away from baby for whatever reason, you’ll want to start adding in daily pumping sessions to ensure that you have enough expressed milk available for your baby while you are away.  The morning is a great time to add in a daily pumping session because the body’s milk production is naturally higher. If you are working on preparing to head back to work and getting your breastfed used to taking a bottle, you’ll know that offering a daily bottle to baby can be useful.  Once you choose a time for baby’s daily bottle this is a perfect time to pump because it is technically a “missed feeding” when they would have nursed.  Remember that while you are away from baby or introducing a bottle at home, pump every time your baby takes a bottle to ensure that you are keeping your supply up and preventing clogged milk ducts.

For more information on these topics see the related articles, Bottle Feeding My Breastfed Baby and Preparing to Go Back to Work as Nursing Mother.

How Long Should I Pump For?

It is tricky to put a number on exactly how long you should pump for to ensure that you are adequately emptying your breasts and yielding the most expressed milk possible. The pump is simply not as effective as baby at removing milk and some women’s bodies never respond to the breast pump well enough to have a full letdown.  Other women are able to easily letdown for the pump and even have subsequent letdowns.  All of that being said, there are some general tips and advice to get the most out of your pumping sessions.

You want to aim to pump for 20-30 minutes or ideally 2-5 minutes after the last drop falls.  It is important to keep in mind that you may not letdown for the pump at first but you will still yield some milk.  If the letdown occurs towards the end of the pumping session, extend the time and wait until after the last drop falls. I know that sometimes I would be pumping for going on 15 minutes and FINALLY my milk would letdown and I would really start yielding expressed milk.  This is a case when the length of time pumping is going to be longer because it is essential to pump until the last drop falls.  Failing to do so can lead to clogged milk ducts and possible infection.

Next to a hospital grade pump, which are typically only used by women who need to exclusively pump for medical reasons associated with them or their baby, a double electric pump is usually better for pumping than a hand pump.  Learning to pump both sides at once will save time and help yield the most from a letdown.  In the beginning you may need to do one side at a time until you become more comfortable with pumping or until you have a pumping bra designed to make this process easier.  It is also worth noting that some moms simply do not respond to an electric pump and find that using a manual hand pump yields greater amounts of milk and promotes better letdowns.

Ensure Proper Fit

There is nothing worse than pumping with ill-fiting parts.  You won’t yield as much milk and you can seriously injure or irritate your nipple.  You want to ensure your pump flanges fit properly. Your pump will come with a standard size but smaller and larger sizes are available.  Some key things to keep in mind are:

  • Nipples should never touch or rub against the flange tunnel, causing irritation
  • Not much of the areola should be drawn into the flange tunnel or rub against the sides of the flange tunnel

If you have any questions or doubt related to the way your pump is fitting or working, a lactation consultant can help ensure that your pump parts fit properly. This is essential for safety, comfort, and optimal milk collection.

Remember! Baby is the Best Pump

If you are reading this article, you are likely pumping because you need to prepare to be away from your baby for some reason or another, however I want to make sure to emphasize this because I have seen too many of my friends become stressed out about supply when they see the amount of milk that they yield while pumping.  What you pump isn’t representative of what baby is getting!  Your body does not respond the same way to the pump as it does to your baby and if baby is gaining weight appropriately and having wet diapers then do not let your yield amounts from the pump stress you out.  Even the best pumps are as low as 50% efficient compared to baby because pumps use only suction, while a baby will use compression and suction combined.

Breastmilk Storage Guidelines

The guidelines in this chart can be used in successive order.  To use the example I mentioned in the intro about my day trip, I pumped in the car and stored milk in storage bags in a cooler.  When I got home that evening I refrigerated the milk for 3 days, and anything that we didn’t use I was still able to freeze.  Just remember that the reverse is not possible.  Once thawed, milk must be used within 24 hours.




61-79 F / 16-26 C4-8 HOURS


59 F / 15 C24 HOURS

3-8 DAYS



FROZEN<39 F / < 4 C



General Rules on Storing Breastmilk:

When you are storing your breastmilk always use sterile and sealed bags.  To avoid waste, I recommend storing in 1-4 oz portions depending on what your baby typically takes at a feeding.  This is because once the breastmilk is thawed for use it must be used within 24 hours and then discarded.  Always include pumping date and time on your storage bags to ensure that you are using the oldest milk in your stash first, and if possible align the time it was pumped with the time it’s given to baby in a bottle.  By starting only a few days ahead of baby in terms of milk needs you can ensure that the milk is best suited for your baby at that particular time in life.  You can find more information about your “stash” in my article about preparing to go back to work.

Other things to note is that separation during storage is normal, as is varied color and ratios of milk fat to liquid.  When preparing expressed milk for a bottle you should always swirl breastmilk, never shake.  If baby doesn’t finish warmed up milk, milk can be refrigerated and offered again for up to 2 hours but then it must be discarded.  When you are leaving milk for your baby, only thaw what you expect they will take on the low end, but leave extra frozen.  This will avoid waste.  For more information about how much milk to leave, read about bottle feeding the breastfed baby.

When it comes time to prepare the bottle these are the key points:

To Thaw:

  • Place in refrigerator for 12 hours to thaw
  • To quickly thaw, run under cool then warm water
  • Use thawed milk within 24 hours or discard

To Warm:

  • Heat water in a container, then place thawed milk in the container
  • Use a bottle warmer

Tips About Pumping “On the go”

Planning to pump while you are in the comfort of your own home or even at work is one thing.  While pumping at work does take some foresight, once you have your supplies and a routine down you can make it work because you know you will have access to consistent storage option, a place to clean or store parts, and a power outlet.  Traveling is a different story.

If you are going to be traveling away from baby there are some things to keep in mind.  You can get a car adapter for your pump.  This will allow you to pump at rest stops or even pull over if need be. If you have a road trip planned a car adapter is a must.  I was able to get a universal adapter that worked great with my pump.

Get a battery pack for your pump if you are not certain you will have access to outlets. Unfortunately, I learned this the hard way. I was visiting my grandma in a big city.  My car was parked in a parking garage so I didn’t have access to use my car adapter while I was there, and not one public bathroom in the hospital where she was staying had an outlet.  It was so stressful! Just when I thought I was going to literally explode from discomfort I begged a nurse to let me use the staff bathroom which did in fact have an outlet.  Lesson learned.  Get a battery pack or at the very least have a hand pump ready!  In an absolute pinch you can always hand express.  But do yourself a favor and have a better back up plan.

Remember that you don’t necessarily have to wash pump parts after every pumping session.  Just like breastmilk is shelf stable for around 2 hours and can be refrigerated for up to 3-8 days without freezing, you can apply these rules to your pump parts.  Though refrigerating for around 24 hours is preferred.  When I was on the go without access to a fridge or sink I popped my pump parts into zip locks and stuck them right in the cooler with my stored milk.  Ready to go for the next pump session.

Do some research.  Many airports have nursing and pumping rooms for breastfeeding mothers.  The caveat, they may be in only one terminal, far from where you need to be.  Find this out ahead of time to plan accordingly.  Call places you are visiting and ask about bathroom outlets, etc.  Ask about access to refrigerators and always plan to bring a cooler bag if you are not certain.  This is the one I use and love.

Hand Expressing

This is an important skill to learn even if you are not at the point of regularly pumping. You can hand express before or during breastfeeding to engage baby or if you don’t have a pump available and need to express milk.  This can also be useful if baby suddenly sleeps for a longer stretch in the night and you wake up in discomfort.  You can use this technique to express to comfort instead of pumping in the middle of the night which is totally annoying.  If you do wake up full and uncomfortable at night and pump you are signaling to your body to make more milk instead of teaching it that baby may not need as much milk at night anymore. This is another reason that hand expressing at night is a great strategy.

How to hand express:

  1. Position your thumb and index fingers in a c-shape (known as a c-hold)
  2. Starting at the nipple, with your thumb on top and index finger on the bottom, pull your fingers towards the base of your breast opening the c-shape wider (This massage will help milk flow)
  3. Pull c-shape and fingers back toward the nipple to essentially “squeeze” milk out
  4. You can vary position of thumb and index finger, especially if you are aiming to clear a clogged milk duct

You’re Ready to Go

With all of this information you are well prepared to pump with correctly fitting parts and store and thaw milk in a safe and appropriate manner. For more information about bottle feeding your breastfed baby, please read my tips about how to pace feed.

If you want to learn about other ways to prepare for your return to work in addition to pumping and storing, learn more in my article about Returning to Work as a Nursing Mother. And because knowledge is power, see everything else we have to offer in our breastfeeding section.

If you like what you’ve read here and are either new to breastfeeding or are trying to learn as much as you can before your baby arrives, sign up for our FREE five-day breastfeeding e-mail course or learn more about our comprehensive breastfeeding handbook which has everything you need to breastfeed successfully.

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