Once you’ve pumped your milk, what do you do with it? You can:
- Feed it to your baby at the next feeding
- Store it in the refrigerator
- Freeze it
Below are summaries and best practices regarding each of these options.
Feeding your baby fresh milk
This is probably the easiest option if it’s feasible for you.
Obviously, it isn’t feasible if you’re not with your baby, like if you’re at work. Also, some moms can become stressed about pumping enough milk to cover the next feeding and prefer to be a feeding or two ahead of their baby. However, if it works for you, it eliminates the need to warm bottles or deal with freezer bags, which is nice.
If you use freshly pumped milk, it can safely stand at room temperature for 4-8 hours. Once you’ve finished pumping, you can set it aside and then give it to your baby when he or she is hungry.
My experience: This was my preferred option when I wasn’t at work and once my supply was stable enough. Also, when I had dropped the middle of the night pump, I took the last pumped milk of the evening upstairs with me to bed and then was able to feed it to my baby in the middle of the night without needing to warm it.
Reusing expressed breast milk
If your baby doesn’t finish a bottle of freshly pumped or refrigerated milk, you can offer it to the baby again at the next feeding. No studies have been done on the safety of using leftover milk; however, various breastfeeding experts indicate that it is likely safe. Some mothers choose to leave the milk at room temperature and others prefer to refrigerate and re-warm.
Personally, I would discard any milk left after a feeding after 4 hours. Additionally, I would not reuse previously frozen milk at subsequent feedings; I would handle it the same way I would handle formula. (Formula must be discarded after the first feeding attempt.)
Using refrigerated milk
Freshly pumped milk will be fine in the refrigerator for 3-8 days. If you have a number of bottles in the refrigerator at any given time, it is a good idea to label them with the pump date (you can use a piece of masking tape) or order them with the oldest bottles in front so that they are used first.
If you are exclusively pumping, it is worth seeing if your baby will take cold bottles, as it eliminates the warming step and makes things much easier when you are out of the house. Some babies don’t mind them (or will get used to them if you gradually make them colder) and others will only take warm bottles.
If you do need to warm the milk, there are a few different ways to do it. You can run it under warm water in the sink, put it in a container of warm water, or you can use a bottle warmer. Never microwave breast milk or formula, as the microwave can create “hot spots” that will burn the baby’s mouth, and make sure to check the temperature after warming by squirting a bit on your wrist or hard.
Over time, cream will rise to the top of the milk as it is stored in the fridge. This is normal and nothing to worry about. If you warm the milk, I find that the warming process does a decent job of mixing it together. If you don’t warm it, swirl it gently to mix. (The recommendation used to be not to shake breast milk, but it’s unlikely this has much of an effect.)
Freezing breast milk
Breast milk can be frozen in glass or plastic bottles or “mother’s milk” bags (these are my favorite, and I’ve had the fewest problems with holes during the defrosting process versus other brands).
Many sources recommend storing milk in 1-4 oz portions. Personally, I have found it easiest to store it in whatever my baby’s current feeding amount was at the time, because it was most likely that that would be the amount that I would need. If I do happen to need less than a full feeding and don’t want to waste the milk, I defrost the bag, pour what I need into a bottle, and put the rest in the fridge for later (usually still in the breast milk bag).
It’s a good idea to give your frozen breast milk a test run with your baby before building a large freezer stash, in case you have a lipase issue.
When freezing the milk, label it with:
- The date the milk was pumped (if you have milk from more than one pumping session in the same bag, use the earlier date).
- The amount of milk in the container.
- Your child’s name (if your child will be using the frozen milk in a childcare setting).
How long frozen milk is good for depends on the freezer:
- In a freezer compartment of a mini-fridge: about 2 weeks
- In a standard freezer: 3-6 months
- In a deep freezer: 6-12 months
To maximize the length of time that milk will last in your freezer, consider regularly rotating your freezer stash.
Using frozen breast milk
There are two approaches to thawing milk. The first is to put in in the refrigerator to the thaw slowly, which will take about 12 hours. The other is to put the container of frozen breast milk in water. Whether you should use hot or cold water depends on when you’ll be using the milk.
If you plan to use the entire bag of breast milk for the next feeding, it’s easiest to put the bag under hot running water or in a container of warm water. This will thaw and warm the milk at the same time, and it’s usually ready to go within 5-10 minutes, depending on how hot the water that you’re using is.
However, if you plan to use only part of the milk – or if you’re defrosting for a later feeding (like if you’re prepping bottles for the next day’s childcare) – you’ll want to use cold water. Then, once the milk is defrosted, you can put it into the bottle that will be used for feeding and back in the fridge.
If you have had problems with leaks/holes in your breast milk bags during the defrosting process, you can try putting a ziploc bag around the one that you’re defrosting before you put it in water. If you’re defrosting in the fridge, put the bag in a bowl to catch any leaks.
Milk should not be thawed at room temperature.
Frozen milk should not be refrozen. Once it has been thawed, it should be used within 24 hours.
Finally, Kellymom has a great printable reference guide regarding storing expressed milk. Also, if you need to travel with breast milk, here are some tips for packing the milk and your stuff.
Hi, when you say freeze the breast milk after pumping, does it mean from pump bottle right to the freezer? Or do you put it in a chiller first to cool it?
I meant straight to the freezer. 🙂 You can put it in the fridge first if you want but it’s not necessary.
Why can’t thawed frozen milk that had been thawed out in the fridge be used after 24 hours?
Thawed frozen milk can’t be used after 24 hours no matter how it was thawed. As far as the “why” – I think that’s when doctors and breast feeding experts believe there starts to be a risk of it getting contaminated. Frozen milk doesn’t have the same antibodies as fresh because of the freezing process, so the milk won’t hold up as well in the fridge. I doubt it’s ethical for them to do a lot of testing as to when thawed milk makes babies sick, so it’s probably an inexact science as to the timeframe they picked. Hope that helps.
Hi.
Can I save my daily EBM in a mason jar and then at the end of the day separate the 4 oz portions into Lansinoh bags?
What about placing breastmilk in a cooler?. I know its good for 24hrs, however how good is it once out of the cooler? Can you re cool any left over milk? Or does it need to be thrown out?
If it was only in the cooler for a few hours, then I would say just put it in the fridge and treat it like you put it in there right away. If it was in the cooler for the full 24 hours, I would either use it or refrigerate and use it as soon as possible (i.e., don’t leave it in the cooler for 24 hours AND then the fridge for 5 days if possible). That’s just my approach though.
If I thaw frozen milk in the refrigerator and it takes 12 hours to thaw does that mean I only have 12 more hours to use it or do I have 24 from the time its completely thawed
Kellymom says you have 24 hours after it finishing thawing:
https://www.kellymom.com/store/freehandouts/milkstorage01.pdf
Hi. I have been refrigerating my breast milk right after pumping then heating in bottle warmer. If there is left over milk can I refrigerate and warm up again for the next feeding? I didn’t think I could heat up the milk twice and was thinking I had to discard it. Thank you!
I usually left it at room temperature (versus putting it back in the fridge and reheating). I looked on kellymom and this exact issue is discussed here, with no certain answer either way:
https://kellymom.com/bf/pumpingmoms/milkstorage/reusing-expressedmilk/
Hope this helps!
When do you start the time if you leave your breast milk in room temperature? When you pump or after?
That’s a good question – I have always done after, but if you wanted to be on the safe side you could do when the pumping session starts.
I’m exclusively pumping but making more than baby is eating
If I were to start freezing can I put all one days wirth of extra into one freezer bag ? When are people using the frozen milk ? Months down the kind will baby still get everything from milk that old ?
Hi Lindsey! Usually the most you can fit into a breast milk bag is 6 oz (thought I’ve fit 8 into a Lasinoh bag). You can use it up to 6mos-1 year later if you have a chest freezer.
I’m exclusively pumping. If I thaw frozen milk and leave it in the refrigerator, then take it out of the fridge (for traveling purposes), how long is the milk good at room temp?
I would probably try to use it within an hour. You could stretch it longer by putting it in a bottle cooler like this:
https://www.amazon.com/gp/product/B002DELZ0K/ref=s9_acsd_zgift_hd_bw_bLoCN1_c_x_w?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=merchandised-search-5&pf_rd_r=EDY0DEKBMQ249MENCPA7&pf_rd_t=101&pf_rd_p=e29bbeb8-ae90-559a-a03f-5ed936183371&pf_rd_i=322267011
Hi,
Can I leave a thawed bottle (out of refrigerator) out in room for over night feeding? Or should I discard it within 4 hours?
Regards,
R
If the thawed milk was ever frozen, then I wouldn’t leave it at room temperature – I would heat it right before use. If it was just chilled in the fridge, it should be fine at room temperature for 6-8 hours (depending on how warm room temperature is in your house).
Hi if I have expressed milk & refrigerated it then heat later during the night to give to my baby & she doesn’t drink it all can I do any of the following?
1. Refrigerate & then re heat again at next feed ?
2. Leave it at room temperature for her next feed
3. No good & throw it?
Also why can you not shake breast milk bottles?
Thanks
Either 1 or 2 is likely fine, but I wouldn’t let it go too long – maybe 3 hours tops is what I would be comfortable with. (Just my opinion, I am not a doctor.) For more info, read:
https://kellymom.com/bf/pumpingmoms/milkstorage/reusing-expressedmilk/
Hi I transfer the frozen milk from freezer to fridge since yesterday evening .. it’s still frozen in the fridge now.. I’m planning to use it for two feedings.. what should I do?
Put it in the sink in warm water when you’re ready to use it.
Maybe increase the temp in your fridge so that milk thaws
Hi there, I have two questions. My baby USB 3 months old and I’m going back to work so will Be pumping for her, but she will NOT take the bottle – any suggestions?
Secondly, has anyone ever frozen their milk in mason jars? – and left them to defrost in the fridge overnight? Worried about glass shattering..
Can you have someone else give her the bottle when you’re not there?
My worry with the mason jars is that you’d have to use the full jar when it defrosts within 24 hours – no room for error if there is any extra in there, it would just go to waste.
Thanks for this article. Quick question. Is it okay after defrosting different bags of milk to combine the milks from different dates in the same bottle?
Yes!
Hello!
Started yesterday back at work full time! I am in a private room to pump and from my left boob I got 5 ounces so I had to switch to a new medela bottle to pump into quickly. Is it OK to leave the milk in the bottle on the counter with the cap on it until I am done and ready to leave the room or should I in-between bring that bottle filled with milk to my mini fridge at work and then come back to do the right boob pump? I just don’t want the milk to go bad while sitting at room temp on the counter.
Do you think my supply will go down? I am pumping in the AM then feeding Arabella. Then when I get to work I pump at 9, 12 and 3. When I pick my daughter up at 3:45 I nurse her right away and all night till 9ish to bond with her and then pump later in the night before bed. Should I do a earlier pump like 2 AM? She sleeps through the night at 2 months so I do too LOL
It’s totally okay to leave it at room temp until you’re done! (it’s fine at room temp for 4 hours).
I think your schedule sounds okay – you can adjust it if necessary but it sounds like you have a good supply? No reason to assume that will change. Good luck!
Can you add freshly expressed breast milk to already refrigerated and cooled breast milk that was expressed within 24 hours of fresh breast milk?
Yes!
Hi,
Once thawed and heated if my baby doesn’t have all of it how long can I keep it for and how do you store it? Can I just put that bottle with the remaining milk in the fridge?
I would probably discard a thawed and heated bottle after an hour (treat it like formula).
Thankyou!
We are trying to get my little girl to take a bottle aswel as breast, I think we may struggle as she won’t even take a dummy, any tips?
Maybe try having someone else give the bottle when you’re not in the room??
Curious: why do you believe in treating thawed breast milk like formula and discard after an hour?
So the instructions on thawed milk are that the milk must be used within 24 hours of thawing. Normally, milk in the fridge is fine for 5+ days. My understanding is that the freezing/thawing process breaks the antibodies down enough that the milk isn’t as resistant (just like formula). However, I’m not a scientist or LC!
How long can i refrigerate milk before I put it into the freezer. I’d like to fill the full 6oz but I don’t get that in one pump yet. Is 48 hours Okay in the fridge and then put into the freezer? Thanks!
Hi! Yes, that’s fine.
I pump 8oz the night before for the next day’s bed time feeding. I then put it in the fridge and reheat it in warm water the next evening for bed time. Some times my LO doesn’t finish all the milk; can I freeze the left over milk for my back up frozen stash? It is fresh refrigerated milk from the night before not unthawed frozen milk.
Hi! I would not do this, because the guidance on milk that is in a bottle your baby drank from is that it is “probably safe to offer at the next feeding” (that’s paraphrased from kellymom). I think you could refrigerate it after the feeding and offer first thing the next morning, but that is all I’d do with it, personally.
Hi Amanda
When a refrigerated breast milk (assume refrigerated for 20hrs) is warmed up.
1) How long can it be kept in the water warmer before feeding?
2) If baby can’t finished the warmed milk, can still keep it back in the water warmer for how long?… to be later re-feed again.
Thank you 🙂
I think it’s probably okay for a few hours – it depends on how warm the warmer is. Kellymom says it’s okay for 3-4 hours at 80-90 degrees. I’m guessing it would be warmer than that at first, but not sure how warm it stays.
Kellymom says it is probably safe to reuse the milk at the next feeding within 1-2 hours. I wouldn’t put it back in the warmer, I would put it in the fridge.
https://kellymom.com/store/freehandouts/milkstorage01.pdf
Hi! Just came across your website and it answered so many questions I had! Thank you! So, I exclusively pump. I made my daughter a bottle last night and she fell asleep without eating it. It was from the fridge and I warmed it in water. I hate to discard 6 ounces of unused breast milk. But she sleeps through the night so it would be many hours until she ate the bottle if I were able to reuse it after it was warmed. So after warmed breast milk isn’t used and I leave it on the counter rather then refrigerating it again (I just feel it’s safer to leave it out then refrigerate it again, am I wrong) is it safe to feed my baby this bottle the next morning?
She didn’t start the bottle, right? That should be okay the next morning. I would use it first thing.
How long can milk that was refrigerated be left out? At night I like to take out my daughters next bottle from the refrigerator on her last feeding. I don’t warm it just let it sit there cool then warm it up when she wakes up. Is that ok?
It depends on the room temperature, but assuming it’s less than 80 degrees, kellymom says 4-8 hours but 3-4 is ideal.
https://kellymom.com/store/freehandouts/milkstorage01.pdf
I did what you are describing with my baby – took freshly pumped milk to bed with me at 10, fed it to my baby if they woke up before 4.
1.
Can I store my milk in the fridge right after pumping? (Warm milk)
2. Cab I store freshly milk into yesterdays milk in the fridge?
Yes to both. For #2, you should consider all of the milk to be “yesterday’s milk” when making decisions about how long it can be in the fridge/freezer once you mix it.
Can I leave new clean milk out 4 to 6 hours the refrigerate if not used?
Yes.
I’m still confused. So…
Frozen Milk Thawed in warmer or hot water-How long do I have to use it?
*After I use it once, can I use it again? If so, how many times after and within how many hours from the first time used? And if so, recool in fridge in between or keep at room temperature?
Frozen milk Thawed in Fridge-How long do I have to use it?
*After I use it once, can I use it again? If so, how many times after and within how many hours from the first time used? And if so, recool in fridge in between or keep at room temperature?
Freshly Expressed Milk not cooled-Need to use it all in 6-8 hours and can keep retrying multiple times while leaving at room temperature?
Freshly expressed milk cooled in fridge or cooler bag-Can use within 8 Days and can use multiple times while recooling in between?
Thank You!
Frozen Milk Thawed in warmer or hot water-How long do I have to use it?
*After I use it once, can I use it again? If so, how many times after and within how many hours from the first time used? And if so, recool in fridge in between or keep at room temperature?
I go by formula rules for frozen milk, so that means one hour to use and you can’t reuse it.
Frozen milk Thawed in Fridge-How long do I have to use it?
*After I use it once, can I use it again? If so, how many times after and within how many hours from the first time used? And if so, recool in fridge in between or keep at room temperature?
same as above
Freshly Expressed Milk not cooled-Need to use it all in 6-8 hours and can keep retrying multiple times while leaving at room temperature?
That is a little more than I would be comfortable with. Leaving on the counter for 2 hours, then using, then cooling, then using 2 hours later would be okay for me. Leaving out for an hour, then using, then reusing 3 hours later, then reusing 3 hours later with it out the whole time – I would not do that.
Freshly expressed milk cooled in fridge or cooler bag-Can use within 8 Days and can use multiple times while recooling in between?
I would only reuse it once.
Also, I would just say that there are no hard and fast rules on this stuff because no one has done research on it. For example, what I am basing “what I would do on” is kellymom saying that it’s “probably fine” to reuse breastmilk at the next feeding. Obviously, your level of comfort may be different. Some people would interpret that as it’s not 100% safe to reuse milk at all, so they aren’t going to do it.
I can’t remember what time I pulled my frozen breast milk out lastnight for my baby at child care today . She ended not going to child care is it okay for me to use the thawed out breast milk I took out the night before to use for tomarrow .
It depends on when it finished defrosting. You have 24 hours from when it finishes thawing.
I don’t know how I have never come across your article before… absolutely amazing and so helpful to all of us moms! I have a 7 month old and exclusively pumped for 6 months building up 2 deep freezes of milk for her. We just started digging in and using my stash because I stopped my milk supply. My question is how or what is the best way to warm up a bag that has been partially thawed while out and about for the day. Currently I take the bags of milk with me in the medela cooler bag with no ice packs. I heat up water and bring in a nuby thermos and put bag in there when I need it. It doesn’t do the job all that great. What is the best and safest way to heat up a bag while out for the day?
Hi Christina! That is actually exactly what I would have suggested doing. I wish I had a better answer for you. If you are able to ask for some hot water at, say, a McDonald’s or Starbucks or something, that might work better? Or just running under hot water in the bathroom? Sorry!
I’m three weeks into EPing and have been shaking bottles when I remove them from the refrigerator to mix in the separated cream. On this page you say never to shake them- why? I’m worried I’ve been doing something bad for my baby now.
There is a whole controversy about it. You can read more below – I think shaking is probably a) fine as long as it’s light and b) not really a big deal anyway.
https://www.yourbreastfeedingguidebook.com/blog/2015/6/4/the-milk-shaking-controversy
Please don’t worry! I shook the breastmilk (hard) for a few months too and my now-6-year-old is totally fine.
Thank you for your swift response. Having read the linked article, I tend to agree with its author that the rest of the expressing process probably puts the proteins under just as much pressure, but if I can limit it by not shaking then I will do.
Hi, I’m exclusively breast feeding my 1 month old son. I want to try to express however I have a couple of questions:
1. If I express and put the milk straight in to the fridge over night, once I take it out in the morning how long do I have to use it (if it is kept in an insulated bottle bag throughout the day)?
2. Can I put express milk straight into the baby bottle and store it in the fridge in the baby bottle?
Thanks
Hi Jenna! Congrats on your baby! To answer your questions:
1) In an insulated container, it should be good for 24 hours (assuming there is a cold pack in it), so you should be fine – https://kellymom.com/bf/pumpingmoms/milkstorage/milkstorage/
2) Yes.
Thank you for your reply, do you know how long refrigerated breast milk would last once it is been taken out of the fridge and in an insulated bottle bag but not with a cold pack?
It depends a bit on the temperature. If you’ll be outside on a hot day, I personally would only let it go for 1-2 hours. At room temperature, probably 4. In the car on a wintery day? More like 6-8. I hope that helps! This is what I would do, I think the kellymom page I linked to has more concrete details on temperature. Good luck!
Hi, I just started expressing for my 2-month old, is it okay to express straight into the feeding bottle and refrigerate the feeding bottle with the teat and all?
I would put a cap on top of the nipple, but yes.
Hi I’m also an exclusively pumping mom .. I’ve been pumping for almost 2months.. I never refrigerate my pump milk .. I store it in one bottle feeder then feed my baby when his hungry .. I usually pump 10-12oz and it take up to 6-8hours for my babys feeding.. Is it ok ? I think she will be drinking it 3-4 times 2hours interval
Hi! It depends on the temperature where you are. Kellymom says the fresh milk is okay for 4-8 hours at room temperature (61-79 degrees F):
https://kellymom.com/store/freehandouts/milkstorage01.pdf
Question. After baby is done eating the EBM can you leave it in the bottle and put it in the fridge? Give it the next day from the same bottle? Or must you discard it? Would you be able to freeze it after one day in the fridge?
Kellymom says it’s probably safe to feed at the next feeding. I would discard after that.
After EBM has been left out at room temp for 6 hours and not used could you put it in the refrigerator ?
Yes, but I would probably use it within the next day and not leave it out again (i.e., warm and feed right away). That’s just personal preference though, not coming from anywhere official.
Hi! If I dont get more than 1oz every time I pump can I combine milk from different pumping sessions?
Yes! Just treat all of the milk as if it was from the first session, after you mix it. So if you mix 4 day old milk with 1 hour old milk, now you should treat the whole bottle as if its 4 days old, if that makes sense.
Hi,
Can I defrost my breastmilk, feed it to my baby. If he doesn’t drink the entire bottle, can I put the milk in the refrigerator and warm it for tomrrows feeding?
Hi! I don’t think this has been studied. Personally, I would not reheat frozen milk – if he didn’t finish it, I would discard it after an hour. I generally treat frozen milk like formula because the freezing process breaks down some of the protective antibodies. However, like I said, it hasn’t been studied and other people might have different opinions.
hi Amanda, I keep the milk in a clean bottle ready with 3oz of chilled (thawed and from the fridge) breast milk on the table ready for his next feed. I also keep 1oz chilled breastmilk in a storage bottle in case he needs a top up.
It’s usually a 2hour interval between feeds hence by the time it’s ready to feed him, so the chilled milk should be around 80F.
Is ok to warm it like that instead of using warmer?
Thanks
Hi Pearl! I think that’s totally fine for milk that hasn’t been frozen. Thawed milk I think I would not leave out at room temperature to heat.
I just wanted to know if u can thaw frozen milk in cold water, put the amount u need in a bottle and leave the bottle out on the counter to get warm. And if so, how long will the milk.be good for? It takes longer to warm the milk when it is in a bottle then in the breast milk bags. That is why I was asking.
Hi, I wouldn’t leave milk that has been frozen out at room temperature personally, but I don’t think there is any research that has ever been done on it. What I would do is thaw it the way you describe, put the amount you need in a bottle, and then when you’re ready to use it, warm it by either using a bottle warmer or microwaving a bowl of water for a minute and then sticking the bottle in the bowl for another minute. OR, just thawing the milk in hot water when you’re ready to use it.
Hi,
I am a traveling mom at work so I have to express when I am away.
I passed about 40oz of milk to hotel F&B to freeze my milk only to find them halfway frozen.
I kept them in cooler bag with techni ice sheets and some ice packs.
When I reached home, those half frozen milk had been fully thawed.
Can I continue to freeze them in the freezer or how quick should I let my baby consume them?
Or do you recommend that I should just travel home with chilled milk rather than frozen ones just in case the freezer from F&B isn’t good enough to freeze the milk 100% in 12 hours?
Typically I will need to travel in the car plus air flight for 12-15 hours before I can access fridge.
Thank you in advance!
Can previously frozen breast milk, defrosted in the refrigerator, be transferred to a cooler until ready to use? If so, how long can it be kept there?
Yes. You should use 24 hours after it’s thawed, and it can be kept there as long as it stays cold in the cooler. Frozen milk shouldn’t come up to room temperature on its own.
If I warmed frozen breastmilk and baby didn’t take it, can I put it back in the fridge and reheat it again for next feeding? If so, how long do I have to use it?
Excellent question. To my knowledge, this hasn’t been studied, so my answer is more “what I would do,” not evidence-based. My thoughts are that if he didn’t drink any of it, you put it back in the fridge immediately, and use it at the next feeding (within 1-2 hours), I think that would probably be okay. If your baby drinks any of it and then refused the rest, I would dump the remaining milk.
Hello! Can I pump breast milk and store directly in an insulated bag and give my months old baby within 8 hours?
Hi Frida! It depends on the temperature inside the insulated bag, but as long as it’s lower than room temperature, you should be fine. Kellymom defines room temperature as less than 79 degrees F. (However, it also says 3-4 hours is ideal, so you might want to throw an ice pack in there if it’s going to be 7-8 hours. But should be okay either way.)
Hello, I would like to know if when I heat from the refrigerate breast milk and my baby didn’t drink from it at all (the milk is still in its bag) can refrigerate again and use it the next day?
You can probably safely reuse it at the next feeding (a few hours later) – I would not wait until longer than that or until the next day.