When it comes to pumping, storing, and prepping your breast milk, there are many different ways to get the job done. Some methods work better than others and, like most things, there are right and wrong ways to store and thaw your breast milk. The most notorious way to warm up your milk — yes, I just used "notorious" and "breast milk" in the same sentence — is by using the microwave. But can you thaw breast milk in cold water? As strange as it sounds, it's not completely ineffective.
According to La Leche League International (LLLI), the safest ways to thaw your frozen milk are by setting it in the fridge the night before you need it or running it under cool water. Since using freezing cold water will make it almost impossible for the milk to thaw and using very hot water runs the risk of overheating your milk, cool or warm water is the best happy medium.
Although there are no harmful side effects of thawing using cold water, it is a bit like trying to cool your food on a hot stove. Baby Gear Lab suggested using lukewarm water to thaw your milk or submerging it in a warm (not hot) bowl of water if you need it sooner.
Using cooler water will gradually thaw your milk, keeping more of the nutrients intact than if you heated it very quickly with hot water or in the microwave. LLLI noted that microwaving your breast milk will not only heat it unevenly (potentially creating pockets of hot liquid that can burn your baby), but it can destroy some of the beneficial properties of the milk.
Before you panic and skip freezing your milk altogether, keep in mind that it's not as complicated as it seems. With a little bit of forethought — meaning, knowing how much milk you'll need for the next day — the temptation to speedily thaw your milk using hot water (or a microwave) will be a non-issue.