Knowing how to warm up breast milk is important for all parents, as long as you’re going to store the freshly extracted milk. That’s a very common situation. Your newborns have little stomachs and will drink a small amount of breast milk. No matter whether you’re breastfeeding or an exclusive pumping mom, you’ll need to bottle-feed your baby with warmed-up breast milk.
This guide will walk you through the best methods for warming up breast milk, address common concerns, and offer tips to store and heat up breast milk to ensure your baby’s health and safety.
Do You Have To Warm Up Breast Milk?
Before diving into the methods of warming up breast milk, you should know if it’s necessary to do this. In most cases, breast milk can be fed to your baby at room temperature. You can pump the milk forehead and pour it into the baby bottle before the baby wakes up.
However, if you take the breast milk from the refrigerator or freezer, you should thaw or warm up the breast milk. Babies are generally adaptable and can drink milk at various temperatures. But make sure the breast milk is near to room temperature for best nutrition and normal taste. Some babies may not drink cool breast milk due to its smell.
As long as you’re planning to warm up the breast milk, you can follow the below tips to warm up the breast milk based on your specific cases and needs.
How to Warm Up Breast Milk from the Refrigerator
If you have stored the breast milk in the refrigerator, you’ll need to warm up this type of breast milk before using it to feed your baby. Warming up breast milk from the refrigerator is a straightforward process. Here’s a step-by-step guide on how to do it:
First, take the breast milk from the refrigerator. We often store the breast milk in disposable milk storage bags. They’re temperature sensitive, ensuring the breast milk warms up rapidly.
Second, warm up breast milk in a warm water bath or bottle warmer. There are two methods for warming up breast milk from the refrigerator:
Warm Water Bath
Place the bottle or storage bag of breast milk in a bowl or sink filled with warm water. Let it sit for 10-15 minutes, gently swirling the bottle occasionally to ensure even heating. This method takes a longer time to warm up breast milk. A newly wake-up baby probably can’t wait so long to eat their meals when they’re hungry, especially at night.

Bottle Warmer
Using a bottle warmer might speed up the warming-up process. They can be set up at a given temperature and warmed up breast milk at that temperature always until the breast milk is ready for feeding. If you have a bottle warmer, follow the manufacturer’s instructions to heat the milk.
Third, check the temperature: Before feeding your baby with warmed-up breast milk, test the temperature of the milk by squirting a few drops on the inside of your wrist. The milk should feel warm, not hot. Ideally, it should be at body temperature (about 98.6°F or 37°C).
You should not use boiling water or direct heat sources to warm up breast milk, as this can destroy valuable nutrients and create hot spots that might burn your baby’s mouth.
How to Warm Thawed Breast Milk from the Freezer
It’s different to warm up breast milk that is taken from the freezer from breast milk taken from the refrigerator. You should thaw breast milk before warming up. So the steps to warm up thawed breast milk require special attention to maintain its safety and nutritional value:
1. Thaw Properly: First, ensure that the breast milk is properly thawed. Thaw frozen breast milk in the refrigerator overnight or place the container under cold running water and gradually warm it with lukewarm water.
The next steps are the same as warming breast milk from the refrigerator.
2. Use a Warm Water Bath or a bottle warmer: Once thawed, use a warm water bath to heat the milk. You should warm up breast milk gradually by placing the container in a bowl of warm water. Swirl occasionally to ensure uniform heating. Or you can get a bottle warmer to speed up the warming-up process to feed a hungry and crying baby.
3. Check Temperature: As with milk from the refrigerator, always check the milk’s temperature before every feeding. It should be warm but not hot. The nearer to room temperature, the better for your baby to accept the warmed breast milk.
4. Avoid Re-Freezing: Once breast milk has been thawed and warmed up, do not refreeze it. Use it within 24 hours to ensure it remains safe for your baby.
How Long Is Thawed Breast Milk Good After Warming?
This is a common question many parents may have. If your baby does not eat all the warmed-up breast milk, you still want to reuse it before going bad. So understanding how long thawed breast milk remains good after warming is crucial to prevent spoilage.
Once you have warmed up breast milk, it should be used within 2 hours. Any milk that has been sitting out beyond this period should be discarded. Also, don’t leave warmed breast milk at room temperature for over 4 hours. If you’re not using it immediately, you should not store it in the refrigerator and reheat it, instead, you’ll need to throw it away.
Can You Microwave Breast Milk?
No. You should never use a microwave machine to thaw or warm up breast milk. It’s not allowed for several reasons:
1. Nutrient Loss: Microwaving can destroy essential nutrients in breast milk, diminishing its health benefits.
2. Uneven Heating: Microwaves heat unevenly, creating hot spots that can burn your baby’s mouth. This inconsistency makes it difficult to ensure that the milk is heated evenly.
Should You Use a Stovetop To Heat Breast Milk?
It’s not recommended to use a stovetop to warm up breast milk. If you do want to use a stovetop, use it to heat the water to give the breast milk a warm water bath. You should not heat breast milk directly. Why? Because you can’t control the temperature of the stovetop precisely. The most appropriate temperature to warm up breast milk is under 50°. It’s difficult to keep a stovetop at that temperate range. Or you’ll need a thermometer to monitor the milk to avoid overheating. That’s not practical and convenient for busy parents.
Go get a bottle warmer to make your life easier. They’re not expensive, around $40.
Do You Need a Bottle Warmer?
If you bottle-feed a lot, then a bottle warmer is a necessity for busy parents. Bottle warmers are a popular tool among new parents for several reasons:
1. Convenience: Bottle warmers are designed to heat milk safely and efficiently. They can be set up at a given temperature, offering a consistent and controlled method of warming up breast milk.
2. Ease of Use: Most bottle warmers come with presets and timers, making it easy to warm up breast milk without guesswork. You don’t need to hold the bottle or storage bag and swirl manually to warm up the breast milk.
Fort portable use. The bottle warmers are not big in size. You can warm up breast milk with it on a bedside table. They can be taken for use even when traveling. For example, if you have to feed your baby on the airplane or in the car, you can warm up breast milk with a bottle warmer
3. Cost Considerations: While bottle warmers can be an added expense, they offer convenience and precision. And they’re relatively cheap if you choose an affordable breast pump over some pricey ones. It’s strongly recommended to have one to simplify your parents’ life.

Can You Reuse Previously Heated Breast Milk?
No. Reusing previously heated breast milk is generally NOT recommended, for the safety reason. We know that the warmed breast milk should be consumed within 2 hours. Reusing milk that has been sitting out or reheating it multiple times can increase the risk of bacterial growth.
Even though every drop of breast milk is precious, to ensure your baby’s safety, always discard any leftover milk and prepare fresh milk as needed.
Best Practices for Handling and Storing Warmed Breast Milk
To ensure the safety and quality of warmed breast milk, follow these best practices:
1. Handle with Clean Hands: Always wash your hands before handling breast milk to prevent contamination.
2. Store Properly: If you have leftover milk, store it in the refrigerator and use it within 24 hours. Never leave warmed milk out at room temperature for extended periods.
3. Avoid Reheating: Reheat only the amount of milk you need. Avoid reheating multiple times to maintain its safety and nutritional value.
Conclusion
Knowing how to warm up breast milk correctly is an essential skill for new moms. By following these guidelines, you can ensure that your baby receives milk that is both safe and nutritious. Whether you choose a warm water bath, bottle warmer, or stovetop method, prioritize safety and avoid methods like microwaving that can compromise the quality of the milk. Remember to check the temperature before feeding, handle milk with clean hands, and store any leftover milk properly.