How Long is Frozen Breast Milk Good For?

Freezing and Defrosting Breast Milk

Pumping and freezing is an effective way to store breast milk for later use. Frozen breast milk can be kept for six to 12 months in a deep freezer.

Whether you're returning to work, building your milk supply, or you just want your partner to be able to feed your baby an occasional bottle, at some point, a good chance exists that you will want to pump and store your breast milk. Once you've pumped or expressed your breast milk into a safe bag or container, you can store it in a cooler with a cold pack for 24 hours, the coldest part of an attached freezer for three to six months, or in a deep freezer for six to 12 months. The sooner you use your pumped milk, the better it will be for your baby.

The Deep Freeze

When you pump breast milk to freeze, be sure to pump or transfer your milk into a suitable container, such as a bottle with a screw cap or a pre-sterilized milk bag. Leave a little bit of space at the top of the container so that the milk has room to expand as it freezes. Use a permanent marker to label the bag with the date you pumped it and your child's name if you plan to take the milk along to a childcare provider. Store the milk in the coldest part of the freezer, toward the back. Do not put it in the freezer door since this area experiences the largest variations in temperature. If you want to add breast milk to a container that is already frozen, cool the newer milk first, and do not add more in ounces than what is already in the container. This prevents the newer milk from defrosting the milk that is already frozen inside the container.

Thawing Out

When you are ready to thaw your frozen milk, always use the oldest milk first. The safest way to thaw frozen breast milk is to put it in the refrigerator for 24 hours and then warm it under warm, running water. If you didn't plan ahead and you need the milk more quickly, take a container out of the freezer and run it under warm water until it reaches room temperature. You also can heat the container gently in a pot of warm water. Shake the container of milk to redistribute the fats once it has warmed.

Keeping It Safe

To keep your breast milk safe for your baby, do not refreeze defrosted milk. Try to defrost only the amount that your baby will eat in a single feeding or in a 24-hour time period, if you are using frozen milk exclusively and defrosting in the refrigerator. As painful as it is, discard any defrosted milk that your baby doesn't drink within 24 hours. Defrost and use the oldest milk first, but keep in mind that using milk as soon as possible after pumping minimizes lost nutrients. Be sure to wash your hands before any pumping session and keep your pump and all its parts clean. Don't defrost pumped breast milk in the microwave; doing so can cause hot spots that burn your baby's throat. Breast milk that has frozen and thawed may have a slightly different color or texture than fresh breast milk, but it is still safe for your baby to drink.

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