Breast Milk Storage

Learning how to pump and store breast milk can make returning to work easier and less stressful. There will also be times during growth spurts when your baby wants more milk than you have ready. The best way to increase your milk supply is to breastfeed or pump more often. It does require some work and careful planning, but it can be done.

How should I store my breast milk?

Breast milk can be stored in a plastic or glass bottle with a sealable top, or in a sterile, sealable breast milk bag. Although you may choose to pump larger amounts at one time, store your breast milk in smaller amounts that you use every day to avoid wasting it. For example, if your baby eats 4 ounces in a feeding, put 4 ounces of breast milk in each storage container. Also make sure to put a label on each indicating when the milk was pumped. You should not add fresh milk to milk that is already frozen.

You could also pour the milk into covered/ sealed ice cube trays that have been thoroughly cleaned in hot water. Let them freeze until hard, store them in freezer bags, then count up the amount of cubes needed to make a full bottle.

Where should I store my breast milk?

Pumped breast milk should be cooled in a refrigerator or other cooler as soon as possible. The milk can also be frozen if you aren't going to use it right away. If you will be storing your breast milk in the freezer, be sure to leave about an inch of room in the bottle to allow for expansion of the milk when it freezes.

How long can I store my breast milk?

The following are some general breast milk storage guidelines:

  • At room temperature (less than 77F) for 4 to 8 hours
  • At the back of a refrigerator for 3 to 5 days
  • In a freezer compartment located inside a refrigerator, up to 2 weeks (for example the freezer compartment in a "mini fridge."
  • At the back of a self-contained freezer for up to 3 months (0 F or -18 C)
  • In a deep freezer (always at 4 F or -20 C) for 6 to 12 months

The breast milk I have in my refrigerator looks funny. Is something wrong?

Frozen breast milk can vary in color, but that doesn't mean it has gone bad. Refridgerated or frozen breast milk can be bluish, yellowish or brownish. It is also normal for breast milk to separate into layers (the fatty part of the milk goes to the top). Shake the bottle or sealed bag, and the fat will go back into the milk.

How should I thaw frozen breast milk?

Thaw the milk slowly by swirling the container of milk in warm water or by putting the container in the refrigerator the day before it is to be used. Don't use hot water to thaw breast milk. Never thaw frozen breast milk in a microwave oven. The milk could get too hot and burn your baby's mouth. Microwaving can also damage valuable proteins in breast milk.

Thawed breast milk can be refrigerated for up to 24 hours, but it should not be refrozen.

Is it safe to microwave my baby's bottles?

The microwave can create dangerous "hot spots" in bottles of formula or breast milk, so you should never microwave them. Instead, you can run the bottle or freezer bag under warm water for a little bit, swirl the bag or bottle around in a bowl of warm water, or thaw the milk in the refrigerator. You can also put your baby's bottles in a pan of warm water (away from the heat of the stove) and then test the temperature by squirting a drop or two on the inside or your wrist before feeding your baby. You also can get bottle warmers for use at home or in the car.

Breast Milk Storage & Feeding Products



This is general information and does not replace the advice of your physician or healthcare provider. If you have a problem you cannot solve quickly, seek help right away. Every baby is different, and your baby may not be average. If in doubt, contact your physician or other healthcare provider.

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