How long does expressed breast milk keep?

How long you can safely keep expressed breast milk depends on the storage method. Consider these general guidelines for healthy infants:

  • Room temperature. Freshly expressed breast milk can be kept at room temperature for up to six hours. If you won't use the milk that quickly or the room is especially warm, transfer the milk to an insulated cooler, refrigerator or freezer.
  • Insulated cooler. Freshly expressed breast milk can be stored in an insulated cooler with ice packs for up to one day. Then use the milk or transfer the containers to the refrigerator or freezer.
  • Refrigerator. Freshly expressed breast milk can be stored in the back of the refrigerator — not the door — for up to five to eight days.
  • Freezer. Freshly expressed breast milk can be stored in a standard refrigerator freezer for up to three to six months and in a chest freezer for up to six to 12 months. Place the milk in the back of the freezer — not the door.

Expressed breast milk is an ideal way to feed your baby when you're apart. Still, some research suggests that the longer you store breast milk — whether in the refrigerator or in the freezer — the greater the loss of vitamin C in the milk. Other studies have shown that refrigeration beyond two days might reduce the bacteria-killing properties of breast milk and long-term freezer storage might lower the quality of fat in the breast milk. It's also important to note that breast milk expressed when a baby is a newborn won't as completely meet the same baby's needs when he or she is older.

Keep in mind that storage guidelines might differ for preterm, sick or hospitalized infants.

How do I thaw frozen breast milk?

Thaw the oldest milk first. Simply place the frozen container in the refrigerator the night before you intend to use it. You can also gently warm the milk by placing it under warm running water or in a bowl of warm water. Before offering the milk to your baby, gently swirl it to evenly distribute the creamy portion of the milk that rises to the top of the container during storage. Don't vigorously shake the container or stir the milk.

Never thaw frozen breast milk at room temperature, which enables bacteria to multiply in the milk. Also, don't heat a frozen bottle in the microwave or very quickly on the stove. Some parts of the milk might be too hot, and others too cold. Some research suggests that rapid heating can affect the milk's antibodies as well.

Use thawed breast milk within 24 hours. Discard any remaining milk. Don't refreeze thawed or partially thawed breast milk.

Does thawed breast milk smell or look different from fresh breast milk?

The color of your breast milk might vary, depending on your diet. Also, thawed breast milk might seem to have a different odor or consistency than freshly expressed milk. It's still safe to feed to your baby. If your baby refuses the thawed milk, it might help to shorten the storage time.

Apr. 06, 2012 See more In-depth