How to Warm Up Breast Milk Safely

Breast milk does not need to be warmed at all. It can be served at room temperature or cold, straight from the refrigerator. If you do choose to warm it, keep the container sealed and stand it in warm water or hold it under warm, not hot, running water for a few minutes, then test a few drops on your wrist before feeding.

• A sealed breast milk storage bag or clean, food-grade container with a tight-fitting lid, made of glass or plastic
• A bowl of warm water, or access to warm running water
• Optionally, a bottle warmer, used according to the manufacturer's instructions
• Your own wrist, for testing the temperature

1. Wash your hands well with soap and water before handling the milk. If soap and water are not available, use an alcohol-based hand sanitiser that contains at least 60% alcohol.
2. Thaw the oldest milk first. Always thaw the oldest breast milk first, because the quality of breast milk can decrease over time.
3. If the milk is frozen, thaw it by putting the container in the refrigerator overnight, in warm or lukewarm water, or under lukewarm running water.
4. If you thawed the milk in the refrigerator, use it within 24 hours. Start counting the 24 hours when the milk is completely thawed, not from the time you took it out of the freezer.
5. Keep the container sealed, then place it into a bowl of warm water or hold it under warm, but not hot, running water for a few minutes.
6. If you prefer a bottle warmer, follow the manufacturer's instructions for that model.
7. Test the milk's temperature by putting a few drops on your wrist before feeding it to your baby.
8. Swirl the breast milk to mix the fat, which may have separated.
9. Feed the milk, and use it within 2 hours once it has been brought to room temperature or warmed.
10. If your baby did not finish the bottle, use the leftover milk within 2 hours. After 2 hours, leftover breast milk should be discarded.

Never thaw or heat breast milk in a microwave. Microwaving can destroy nutrients in breast milk and create hot spots, which can burn a baby's mouth. Do not heat breast milk directly on the stove either.

Never refreeze breast milk after it has thawed.

Once breast milk is brought to room temperature or warmed, use it within 2 hours. If your baby leaves milk in the bottle, that leftover milk should also be used within 2 hours and discarded after that.

Breast milk does not need to be warmed, so if your baby is happy with cold or room-temperature milk, you can skip warming altogether.

For storage before warming: freshly expressed or pumped milk can be kept at room temperature (77°F or colder) for up to 4 hours, in the refrigerator for up to 4 days, and in the freezer for about 6 months is best, with up to 12 months acceptable. If you do not think you will use freshly expressed milk within 4 days, freeze it right away to help protect its quality.

Store milk in small amounts, 2 to 4 ounces or the amount offered at one feeding, to avoid wasting milk. Leave about one inch of space at the top of the container because breast milk expands as it freezes, and do not store breast milk in the door of the refrigerator or freezer.

Clearly label breast milk with the date it was expressed, and if you deliver it to a childcare provider, label the container with the child's name as well.

If you are travelling, breast milk can be stored in an insulated cooler with frozen ice packs for up to 24 hours. At your destination, use the milk right away, store it in the refrigerator, or freeze it.

Do I have to warm breast milk at all? No. Breast milk does not need to be warmed and can be served room temperature or cold.

Can I use the microwave to warm breast milk? No. Never thaw or heat breast milk in a microwave, because it can destroy nutrients and create hot spots that can burn a baby's mouth.

How do I know the milk is not too hot? Test the milk's temperature by putting a few drops on your wrist before feeding it to your baby.

How long can warmed milk sit out? Once breast milk is brought to room temperature or warmed, use it within 2 hours. If your baby did not finish the bottle, use the leftover milk within 2 hours, then discard it.

Can I refreeze breast milk after thawing it? No. Never refreeze breast milk after it has thawed.