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.