If you’re pumping and storing breast milk, there may come a time when you or someone helping care for your baby needs to thaw and warm milk. While it may seem straightforward, there are a few important safety tips that can help protect the quality of your milk—and your baby’s health.
Whether you’re heading back to work, sharing feeding duties with a partner, or leaving breast milk with a grandparent or childcare provider, this guide will walk you through the best practices for thawing and warming breast milk safely.
Rule of 4-4-6: Easy Breast Milk Storage Guidelines to Remember
When it comes to storing breast milk, many parents and caregivers find it helpful to remember this simple guideline shared by lactation professionals and supported by the Academy of Breastfeeding Medicine and the Centers for Disease Control and Prevention:
· Up to 4 hours at room temperature (freshly pumped milk)
· Up to 4 days in the refrigerator
· Up to 6 months in the freezer is ideal
· Up to 12 months in the freezer is acceptable
Thawing Frozen Breast Milk
Breast milk is incredibly resilient, but how it’s thawed matters. According to evidence-based guidelines from the Academy of Breastfeeding Medicine, there are three safe ways to thaw frozen milk:
· Place the sealed container in the refrigerator
· Set the container in a cup or bowl of warm or lukewarm water
· Run lukewarm water over the container
Choose the method that works best for your timeline—but keep these important DOs and DON’Ts in mind.
DO:
· Thaw the oldest milk first (think: first in, first out)
· Keep the container sealed while thawing
· Use milk thawed in the refrigerator within 24 hours from the time it is completely thawed
· Use room-temperature or warmed milk within 2 hours
· Use leftover milk from a feeding within 2 hours after your baby finishes
DON’T:
· Do not thaw or heat breast milk in the microwave
· Do not refreeze thawed breast milk
Microwaving breast milk can create hot spots that may burn your baby’s mouth and can damage valuable immune and nutritional components. Gentle warming is always the best way to defrost frozen breast milk.
Warming Refrigerated Breast Milk
Many babies are perfectly happy drinking breast milk cool or at room temperature. But if your baby prefers warm milk, that’s okay too!
To safely warm refrigerated milk:
· Keep the container sealed
· Place it in a bowl or pot of warm water for a few minutes or run warm tap water over it
· Warm breast milk first, then swirl to mix any fat that may have separated
· Test the temperature by placing a few drops on the inside of your wrist—it should feel warm, never hot.
A quick reminder: separation is completely normal! The cream layer that rises to the top is full of healthy fats and should be mixed back in gently before feeding.
Why Proper Handling Matters
Breast milk is more than just nutrition—it contains antibodies, enzymes, and living cells that support your baby’s immune system. Using safe thawing and warming methods helps preserve these benefits while reducing the risk of bacterial growth.
Consistency is also key. When caregivers follow the same guidelines, everyone feels more confident—and baby stays safe and well-fed.
Share With Your Caregivers
If you’re pumping milk, share these guidelines with anyone who feeds your baby, including your spouse, partner, grandparents, babysitters, and daycare providers. Download the CDC breast milk storage guidelines handout HERE. It’s a great resource to print, post on the fridge, or share digitally—so everyone helping feed your baby can do so safely and confidently.
Looking for More Breastfeeding Resources?
If you’re looking for more evidence-based guidance on flange size, milk storage, returning to work, or ordering a breast pump through insurance, visit our Learning Center HERE. You’ll find trusted evidence-based articles that support you through every stage of your parenting journey—from pregnancy to breastfeeding and beyond.
Source:
Academy of Breastfeeding Medicine Protocol Committee. (2017). ABM Clinical Protocol #8: Human milk storage information for home use for full-term infants, revised 2017. Breastfeeding Medicine, 12(7), DOI: 10.1089/bfm.2017.29047.aje
American Academy of Pediatrics. (2025). Milk storage guidelines. https://www.aap.org/en/patient-care/breastfeeding/milk-storage-guidelines/
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