Microwaving Breastmilk: Why It's a No Go

Posted by Jane Springston on

As busy parents, we’re always looking for ways to make our lives easier with all that’s required to take care of a new baby. And there is absolutely nothing wrong with that! And because of its ease factor, we've probably all wondered at one time or another if it's OK to microwave breast milk. Unfortunately, this isn’t one of the shortcuts that you should take.  

Microwaving breastmilk is not recommended for two main reasons.

  1. Microwaves heat food and liquids unevenly and the hot spots that a microwave can create in your baby’s breastmilk risks burning your baby’s mouth and throat.

  2. Microwaving will heat your baby’s breastmilk past the point of where it will begin to deteriorate or break down its health properties. Because microwaves heat unevenly, even a short bout in the microwave can heat parts of the milk well past this point.

Let’s take a deep dive into why you should avoid microwaving your baby’s breastmilk (even when it takes a couple of minutes off your prep time.) Then read on for our suggested warming alternatives that will keep your baby healthy and safe.

Why You Should Never Microwave Breastmilk

Even if you’ve already heard that you aren’t supposed to microwave breast milk, you may wonder if it’s really as big of a deal as everyone makes it out to be. Like, what if you just did it once in awhile...is that OK? The truth is that it’s just not worth the risk. And the loss of nutritional benefits counteracts the entire point of giving your baby breastmilk in the first place. 

Here’s a closer look at why it’s always best to avoid microwaving breastmilk.

Microwaving Creates Dangerous Hot Spots in Liquids and Food

Microwaves are an everyday convenience that most of us couldn’t live without. What you’ve surely noticed in using one is that after heating for a period of time, part of your food will be burning hot while the other half is still cold. While simply annoying for us, this is actually what makes heating breastmilk in the microwave dangerous for your baby.

Because of uneven heating temperatures, microwaves can cause what are called “hot spots” in your baby’s breastmilk. You may think you would notice if your baby’s milk was too hot, but you probably wouldn’t. This is because the outside of your baby’s bottle can still be completely cold to the touch with spots inside that are scalding hot.

The FDA writes, Heating breast milk or infant formula in the microwave is not recommended. Studies have shown that microwaves heat baby's milk and formula unevenly. This results in "hot spots" that can scald a baby's mouth and throat.”

The risk just isn’t worth the extra minute or two you’ll save from microwaving a bottle. We have solutions coming up about safe ways to warm a bottle instead.

Microwaving Causes Breastmilk Components to Deteriorate 

Hot spots are the major safety concern when it comes to microwaving breastmilk, but the nutritional value of that breastmilk becomes compromised in the microwave, as well. 

It’s not that you can’t warm breastmilk at all, there are completely safe ways to do so, but a microwave will bring the breastmilk past the temperature at which breastmilk begins to lose the properties that make it your baby’s superfood.

At what temperature does damage to breastmilk occur?

According to this study, “human milk nutritional and immunological values begin to deteriorate” at 104 degrees and higher. They go on to say that at 122 degrees Fahrenheit, “the rate of the milk quality deterioration increases significantly.” 

Now if you’re thinking you would NEVER warm your baby’s milk to 122 degrees, it’s important to understand that since microwaves heat unevenly, it is very possible that there are certain parts of your baby’s milk that WILL get this hot. Plus it’s probably not as hot as you think. 104 degree temperature breastmilk is usually described as “lukewarm” whereas boiling doesn’t happen until 212 degrees. In other words, it is very likely that a microwave is heating your baby’s milk much higher than 122 degrees.

Though the microwave will surely damage your baby’s breastmilk, other methods (such as placing a bottle into a pot of boiling water) will also make the breastmilk hot enough for this deterioration to occur.

How Breastmilk Deteriorates When It’s Too Hot

As living nourishment, breastmilk is affected by temperature. Solid scientific evidence shows that breastmilk begins to lose its “superpowers” when heated past 104 degrees. Here are the ways that human milk changes and deteriorates as it gets too hot:

  • immunologic and anti-inflammatory components such as SIgA antibodies, lactoferrin protein, and lysozyme (infection protectant) are decreased
  • beneficial probiotic bacteria are destroyed
  • white blood cells are destroyed, in turn decreasing anti-infective properties
  • Fat content decreases which is vital for infant growth
  • Inactivation of digestive enzymes

As a parent who is working hard to give your baby what is considered to be the “gold standard” for infant nutrition, you can see why it’s so important to take care that you’re not overheating your baby’s breastmilk - in the microwave or otherwise.

Safe Warming Alternatives to a Microwave

Microwaves are clearly not a safe way to warm your baby’s breastmilk and you want to be sure you avoid any practice that will heat the breastmilk past 104 degrees. Anything under this temperature is fine and Mother’s Milk Bank states that give your baby body temperature milk is ideal. Cooler than that or even cold are completely safe options as well if your baby will take it this way.

Luckily, there are plenty of ways to warm your baby’s bottle of breastmilk in a safe manner while keeping all its valuable properties in tact. 

Here are the best warming options:

1. With a Bottle Warmer

Bottle warmers offer convenience while making the warming process mess-free. But you still need to take care to choose a bottle warmer that you can be confident won’t overheat your baby’s bottle.

The Baby’s Brew is our go to bottle warmer for ensuring the perfect temperature for breastmilk. Parents can choose from four different temperatures settings, including the perfect temp. Of 98.6 degrees for breastmilk. This battery-operated portable bottle warmer lets you warm your baby’s milk anytime, anywhere while knowing you’re giving your baby breastmilk with the exact nutritional profile to thrive and stay healthy. 

RELATED: Choosing the Best Baby Bottle Warmers for Breastmilk

Though we can’t recommend investing in a bottle warmer enough, there are two other options you can utilize to safely warm breastmilk if you don’t have one.

2. In a Bowl of Warm Water

When you’re at home, an easy way to warm a bottle safely is in a bowl of warm water. With this method you’ll simply fill a bowl with warm water and place the bottle inside until the bottle comes to a lukewarm temperature. What can be tough with this method is knowing that your baby’s breastmilk is staying under the 104 degree mark. To avoid making it any warmer, you never want to use hot water in your bowl. But that’s why we love the Baby’s Brew...there’s no guesswork!

3. Holding it Under a Warm Faucet

The last method for safely warming a bottle of breastmilk is by holding it under a faucet of warm running water. Just like when you use a bowl of warm water, you want to make sure that the water that’s coming under the faucet is not too hot. You should be able to hold your hand under the running water. If you have to pull your hand away, then it’s too hot of water to use to warm your baby’s bottle of breastmilk.

No matter which option you choose, make sure you test your baby’s breastmilk by placing a drop on your wrist. It should feel lukewarm.

Skip the Microwave to Warm Breastmilk

The bottom line is it’s just not worth it to warm your baby’s breastmilk in the microwave even just once. If you have access to a microwave then that means you have access to warm water and there’s no reason to risk ending up with breastmilk that has dangerous hot spots or lost nutrients. A reliable portable bottle warmer where you can choose the exact temperature is your best bet.

For more on safe practices for breastmilk read: 4 Best Tips for Handling and Storing Breastmilk

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