Defrosting Breast Milk

How to Thaw, Warm, and Use Frozen Breast Milk

How To Defrost, Warm, and Use Frozen Breast Milk
You can defrost and warm up breast milk in a bowl of warm water. William McKellar/Getty Images

Defrosting Breast Milk

Breast milk can be collected and frozen to be transported, shipped, or stored for up to a year. But, what do you do when it's time to defrost, warm, and use your frozen breast milk?

When you defrost your breast milk according to the guidelines, it maintains more of its nutrients, and it's less likely to spoil. It's also important to thaw and warm your breast milk properly so that you don't burn your baby's mouth and throat.

Here are some tips for safely thawing out, warming, and using your frozen breast milk. 

Note: These guidelines are for healthy, full-term infants and older children. If you have a premature baby or a child with a compromised immune system, talk to your health care provider for more information on how to collect, store, and use your breast milk.

How to Thaw or Defrost Your Breast Milk

  • Your frozen breast milk should be dated. Defrost the oldest container of breast milk first.
  • You can defrost your frozen breast milk by placing it in the refrigerator, putting it in a bowl of warm water, or holding it under warm running tap water.

  • Thawing breast milk in the refrigerator can take several hours, so be sure to plan ahead. You may want to place a full day's worth of frozen breast milk in the fridge each night so that it will be ready to use the next day.

  • To thaw breast milk using a bowl of water, fill a bowl or pan with warm water and place the frozen container of breast milk into it. As the water cools down, empty the cool water and replace it with more warm water. Continue to do this until the breast milk is no longer frozen.

  • The fastest way to defrost breast milk is to hold it under a faucet of warm running water until the breast milk has thawed.

  • Never thaw frozen breast milk in the microwave. The high heat from the microwave can destroy some of the healthy properties found in the breast milk. Microwaves also cause uneven heating and hot areas in the milk. Hot spots in the breast milk can burn your baby's mouth and throat.

  • Do not place the breast milk in a pot of boiling water on the stove. The breast milk may get too hot, and it can spoil.

How to Warm and Use Defrosted Breast Milk 

  • Defrosted breast milk can be warmed and used immediately, left out at room temperature for up to 4 hours, or placed in the refrigerator for up to 24 hours.

  • Once you defrost your frozen breast milk, it can be given to your baby directly from the refrigerator, or warmed up to room temperature or body temperature. If you choose to warm your breast milk, you can do so by placing it in a bowl of warm water for a few minutes, holding it under warm running water, or using a bottle warmer. You should NOT heat breast milk in the microwave, or in a boiling pot of water on the stove.

  • During storage, breast milk separates into layers. Once you defrost and warm your breast milk, gently swirl or shake the container to mix the layers of milk before feeding it to your baby.

  • Check the temperature of the breast milk before giving it to your child by squirting a few drops on the inside of your wrist. It should not feel hot or cold.

  • Try only to thaw what you need because any leftover breast milk will have to be thrown out after 24 hours. Once you've defrosted your breast milk, it cannot be placed back into the freezer again.  

  • If your baby does not finish a feeding, throw away the remaining milk. Do not reuse any breast milk that is left over after a feeding.

  • Defrosted breast milk may have an unpleasant odor or a soapy, metallic taste. That doesn't mean the milk has gone bad, and you don't have to throw it away. These changes occur naturally in the breast milk as the fat breaks down. It's still safe to give to your baby, but your child may not like the taste of defrosted breast milk and could reject it.

See Also:


American Academy of Pediatrics. New Mother’s Guide To Breastfeeding. Bantam Books. New York. 2011.

Lawrence, Ruth A., MD, Lawrence, Robert M., MD. Breastfeeding A Guide For The Medical Profession Seventh Edition.  Mosby. 2011.

Riordan, J., and Wambach, K. Breastfeeding and Human Lactation Fourth Edition. Jones and Bartlett Learning. 2014.

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