Methods for Thawing Rewarming and Using Frozen Breast Milk

How to defrost breast milk. Learning how to appropriately store and defrost breast milk may make time away from your infant much less stressful.

While you're away, your baby will thrive on breast milk that has been expressed. If you have some milk, how do you go about storing it and using it properly?

Learning how to appropriately store and defrost breast milk may make time away from your infant much less stressful.

Sometimes you won't be able to feed your kid just when they need you to. This might be the case if you're going back to work or school, have some errands to do, or just want to go out for the evening. The ability to save breast milk and provide it to the caretaker makes the transition from mother to caregiver less stressful. This will ensure that your kid continues to get the health advantages of breast milk even while you are apart from him or her.

Breast milk may be used immediately or stored in the freezer for later use. However, there are several things to remember to ensure the milk is safe for your baby. Whether you're preserving fresh breast milk or thawing frozen breast milk, there are different recommendations to follow.

If you're nursing, you may ask the WIC staff about the best ways to store your breast milk.

Where should I store My Breast Milk?

If you're going to feed your baby breast milk, it's best to give them the milk as soon as possible after you've expressed it rather than storing it in the fridge or freezer. Freshly expressed milk offers more antioxidants, vitamins, and fat than milk that has been refrigerated or frozen, and it also has the finest bacteria-fighting capabilities.

Breast milk may be collected and frozen by many nursing mothers. Even if you don't need to ship or carry it, you should probably make a supply nevertheless in case you ever need to be away from your infant or decide to stop nursing. In case you've frozen breast milk for later use, here's how to defrost, reheat, and consume it properly.

The Optimal Length Of Time For Storing Expressed Breast Milk.

After thorough washing, breast milk may be stored at room temperature, refrigerated, or frozen until it is needed.

Keep your newly expressed breast milk at these recommended temperatures and locations (for healthy-term babies)

Place of Stowage Room temperature
16 °C to 25 °C
(60 °F to 77 °F)
4 °C (39 °F)
or colder
-18 °C (0 °F )
or colder
Previously frozen
breast milk thawed
in the refrigerator
Time for safekeeping

Up to four hours is best

Up to six hours for milk expressed under very clean conditions

Up to four hours is best.

expressing breast milk might take up to six hours. Under sterile circumstances, 

We recommend Up to six months is best

Under ideal circumstances, breast milk may be stored for up to nine months.

Two hours or more at room temperature

Up to 24 hours in the refrigerator

Don't freeze again


If you want your breast pump to be under sterile circumstances, you need to follow the steps outlined in our article on the subject. If you have any questions about how to properly freeze and thaw breast milk, you should talk to a lactation consultant or nursing expert.

Your hospital may have more stringent cleaning and storage instructions if your infant is in a neonatal intensive care unit (NICU) or special care ward.

Labeling bottles or bags with the volume and date pumped is essential for keeping track of and managing stored expressed milk.

Breast Milk Guidelines For Expressed Milk

The fat (cream) in breast milk rises to the top when it is stored. Before giving the bottle to your infant, give it a little shake to combine the layers. Some of the milk's protective and nutritious components may be destroyed by vigorous swirling or shaking.

Bacteria from your baby's lips might easily make it into expressed breast milk when he or she drinks from a cup or bottle. To that end, any breast milk that isn't completely consumed within an hour and a half of his first feeding should be discarded. If you've extracted milk for your baby, it's best to just keep enough for one feeding.

RELATED:  how to warm baby bottles

Refrigerator-Safe Techniques For Storing Breast Milk

For proper cold storage of extracted breast milk, please refer to the following:

The breast milk should be refrigerated as soon as possible once it has been expressed.

Breast milk should be kept in sterile containers or BPA-free storage bags. Despite its widespread usage in the past, BPA is now being phased out by several manufacturers because of concerns about its potential long-term consequences.

As long as the additional expressed milk is cold in the refrigerator, you may add it to the same container. Milk at room temperature should not be added to cold milk.

Breast milk should be kept in the refrigerator's coldest section, which is usually the far back, on a shelf above the vegetable bin. It shouldn't be stored on the refrigerator door, where the temperature fluctuates more.

Instructions for Freezing Breast Milk

To learn how to freeze breast milk without worrying about spoiling, keep reading!

When you're done expressing your breast milk, immediately place it in freezer bags.

Breast milk that has been expressed and chilled in the refrigerator may be combined with frozen breast milk. Milk at room temperature should not be combined with frozen milk.

Store milk in smaller quantities for faster thawing and reduced waste (less than 60 ml). After defrosting, they may be mixed together.

Be sure that the breast milk containers you want to use can withstand freezing conditions; glass bottles, for example, might break when exposed to extreme cold. Freezer-safe, pre-sterilized, and labelable, Medela breast milk storage bags are the best option for keeping frozen breast milk.

Keep in mind that breast milk swells when frozen, so filling bottles or bags to the top is not recommended.

Frozen breast milk should be kept at the coldest part of your freezer, which is usually the very back. Avoid placing anything against the walls of a freezer that defrosts on its own.

Breast Milk From a Frozen Supply

Breast milk retains more nutrients and has less of a chance of going bad when thawed safely from frozen.1

Keep your breast milk in freezer-safe bags or containers and identify them with the date they were frozen. Empty the oldest breast milk jar first.

To thaw frozen breast milk, you may either store it in the fridge overnight, place it in a dish of warm water, or hold it under warm running tap water. Freezing breast milk is safe, but you should never let it defrost at normal temperature.

Do not heat breast milk in a microwave or put it in a saucepan of boiling water on the stove. Once breast milk has been defrosted, it may be used immediately, left at room temperature for up to four hours, or refrigerated for up to 24 hours.

These recommendations apply to older children and newborns who have reached full term. Talk to your doctor about collecting, storing, and using your breast milk if you have a preterm infant or a kid with immune system issues.

Refrigerator Breast Milk Defrosting

It's important to prepare ahead of time since thawing breast milk in the fridge might take up to 12 hours. When using frozen breast milk, it's recommended to defrost and store enough for the following day in the refrigerator each night. Breast milk may be defrosted in the fridge in two ways:2

  • Take out of the freezer the container in which the frozen breast has been stored.
  • Put it in the fridge right away.
  • Hold off on drinking it until the frozen milk melts back into a liquid.
  • You should consume the milk within 24 hours of it thawing.
  • Breast milk that has been thawed for more than 24 hours should be discarded rather than refrozen.

Thawing Breast Milk in a Bowl of Warm Water

A basin of warm (not hot) water may be used to swiftly defrost breast milk from the freezer. If you keep an eye on the water and replace it as soon as it cools down, this process may be completed in about 20 minutes. I'll show you how:

  • Prepare some hot water in a pan or basin.
  • Submerge the frozen breast milk carton in the tub. It's important to avoid getting breast milk contaminated by keeping the water level in the bottle below the top.
  • Drain the water and replenish it with hot water as it cools.
  • If the breast milk is still frozen, repeat the process until it is no longer cold.
  • You may refreeze the milk once it's been defrosted, or you can keep warming it up to feed your baby.

Thawing Breast Milk Under Running Water

Holding frozen breast milk under warm flowing water is the quickest method to thaw it. You may do the following steps:

  • Put the bag or other container you'll be using under cold running water to start.
  • Raise the temperature of the flowing water gradually; hot water is not needed.
  • The milk will defrost if you keep the container submerged in hot water.

It's possible that thawed breast milk will have an unpleasant odor. It sometimes tastes soapy and metallic. This does not necessarily indicate that the milk has gone spoiled. An enzyme called lipase gives milk its distinctive sour flavor and aroma. During storage, the milk's lipids are broken down naturally by an enzyme called lipase. Still, it's OK to feed your infant the milk, even if he or she doesn't enjoy the flavor.

Warming Up Thawed Breast Milk

Breast milk that has been thawed in the fridge may be fed to a baby at room temperature or at body temperature. It's possible to warm breast milk in a few different ways: by placing the bottle in a basin of warm water, by holding it under hot running water, or by using a bottle warmer.

Breast milk should not be heated in the microwave or a saucepan of boiling water on the stove.

Properly warming breast milk prevents burns to the baby's lips and throat.

Once the milk is at a comfortable temperature, gently swirl the container to combine any layers that may have formed during storage. Before feeding it to your baby, make sure the milk is at a safe temperature. A few drops squirted onto the inside of your wrist will do the trick. The ideal temperature is lukewarm. Both heat and cold are unacceptable.

RELATED: How to warm breast milk

Possible Health Risks From Microwave and Stove Use

It is not recommended to use a microwave to defrost or heat frozen milk. Some of breast milk's beneficial characteristics may be destroyed by the microwave's high heat. Breast milk may have hot spots due to microwaves' inefficient heating. Your baby's lips and throat are especially vulnerable to these hotspots.

Similarly, warming breast milk over a stovetop is not advised. Overheating may occur if breast milk is heated in a saucepan of boiling water on the stove. Milk loses its nutritional value and becomes too hot for your baby if you cook it for too long.

Warming Breast Milk: Best Practices

If you know how to store and utilize breast milk properly, you can keep it from going bad or becoming a breeding ground for germs.

Some advice is as follows:

  • Breast milk, after being warmed, may be given to the baby immediately or refrigerated for up to 24 hours.
  • Breast milk should never be allowed to sit out at room temperature when still warm.
  • Please do not put it back in the freezer.
  • Breast milk in a bottle that your baby does not complete should be discarded.

FAQs How To Defrost Breast Milk

Q. How long does it take to defrost breast milk?

Around 12 hours -  Breast milk can be defrosted in the fridge, normally in around 12 hours. Alternatively, hold the bottle or bag of frozen milk under warm running water (a maximum of 37 °C or 99 °F). Don't leave frozen breast milk to defrost at room temperature.

Q. Can you leave frozen breast milk out to thaw?

Don't Thaw at Room Temperature. As a living fluid, breast milk should never be thawed at room temperature.

Q. What might have caused the strange odor in my previously saved breast milk?

Breast milk stored in the refrigerator or freezer may take on a distinct aroma. Because an enzyme called lipase degrades lipids and releases fatty acids, this mechanism inhibits the development of pathogenic microorganisms.

Some mothers claim that their frozen breast milk smells like detergent or spoiled food. If you have stored it properly according to the instructions in this article, however, it should be OK to use.

Q. Why you should not shake breast milk?

Should I swirl or shake breast milk? Breast milk will separate because it is not homogenized, meaning the cream will rise to the top. Before feeding, gently swirl the container to mix the cream back through. Do not shake vigorously however as this breaks up the proteins which are so vital for the baby's gut lining.

Q. How do you defrost frozen milk quickly?

To speed up the process of defrosting milk, you can immerse the container of milk in cold water (such as in the sink), replacing the cold water regularly as it warms up. It is not advisable to thaw milk at room temperature as it affects its quality and increases the risk of harmful bacteria growth.

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