Breast milk storage can be confusing – especially when it comes to mixing breast milk. Can you mix thawed and fresh milk? What about mixing milk from different sessions? Here’s what you need to know.
This post may contain affiliate links, which means that if you click through and make a purchase, I’ll be compensated at no additional cost to you. I only recommend products I love! More info here.
Can you mix milk from the different sides of the same pumping session?
Yes, there are no issues with this.
Just pour from one bottle or bag into the other, and store. Label the milk with the day you pumped it, and use it within the breast milk storage guidelines.
Can you mix milk across pumping sessions?
Yes, you can. You just want to treat the combined milk as if it was all pumped at the time of the first expressed.
(Note: The recommendation when mixing milk used to be to make sure that the temperature of the milk that you are combining is all the same – usually, all chilled. However, the American Academy of Pediatrics recently updated their guidelines on this to state that mixing warm and cold milk is acceptable.)
This is ensure that bacteria isn’t given too much time to grow in the oldest milk.
Let’s go through an example.
Say that you pump at 10pm on Tuesday, 1am on Wednesday, and 6am on Wednesday, and then you combine all of that milk into one pitcher or bottle.
You’d label the combined milk and treat it as if it was all pumped at 10pm on Tuesday, because you need to use the first date/time that milk was expressed.
Is mixing frozen breast milk okay?
Yes, you can. Let’s talk about mixing it to freeze, and mixing it to feed.
Mixing breast milk to freeze
Before you freeze breast milk, you can mix milk from different sessions. Just follow the guideline we discussed above regarding labeling with the date of the first expressed.
Then can you freeze it and treat it like any other frozen breast milk.
Mixing frozen breast milk to feed
You can also take thawed frozen milk from multiple containers and combine it for feedings.
Mix thawed milk with fresh milk before feeding is also okay.
How does mixing cereal with breast milk work?
When it’s time to start solids, if you want to feed baby rice cereal or oatmeal, you can mix breast milk into the cereal instead of water. Just stir breast milk into the cereal until it’s the desired consistency.
You can also use breast milk to thin out pureed solids.
Breast milk storage guidelines still apply when your milk is added to solid foods.
Per the CDC:
Don’t put cereal in a bottle. Putting infant cereal in your baby’s bottle will not make him or her sleep longer and could increase your baby’s risk of choking.
What about mixing breast milk and whole milk?
This is fine to do. Prep the bottle of breast milk and add the desired amount of cow’s milk.
(I did this to transition my baby off of breast milk. I started with mostly breast milk and just a splash of cow’s milk, and slowly increased the amount of cow’s milk in the bottle.)
Is mixing breast milk and formula okay?
Yes. Prep the formula on its own, and then combine it with breast milk. Don’t mix the formula with breast milk until you’ve already prepared it on its own (unless your pediatrician has given you different instructions).
When handling the mixed milk, make sure to follow both the timelines on the container of formula in terms of how long it can be out before being discarded, as well as the relevant breast milk storage guidelines for your milk.
More on mixing formula and breast milk here.
Hopefully this answers any questions that you have about mixing breast milk! Let me know if you have any questions in the comments.
Confused about all the rules for handling breast milk in different situations? Worried you’re throwing away milk that you don’t have to? Not sure how to travel with your milk or feed baby on the go? Check out the Ultimate Breast Milk Storage Workshop here! Use MILK10 for 10% off.References
- Anne Eglash, Liliana Simon, The Academy of Breastfeeding Medicine, Wendy Brodribb, Sarah Reece-Stremtan, Larry Noble, Nancy Brent, Maya Bunik, Cadey Harrel, Ruth A. Lawrence, Yvonne LeFort, Kathleen A. Marinelli, Casey Rosen-Carole, Susan Rothenberg, Tomoko Seo, Rose St. Fleur, and Michal Young.Breastfeeding Medicine.Sep 2017.390-395. http://doi.org/10.1089/bfm.2017.29047.aje
- “Feeding from a Bottle.” CDC https://www.cdc.gov/nutrition/infantandtoddlernutrition/bottle-feeding/index.html