“Is it OK to defrost frozen breast milk from a deep freezer overnight in the refrigerator and then re-heat per guidelines?”
This is a fine way to do things. How long the milk is frozen doesn’t really change how it should be thawed. Refrigerate over night or placing the bag in a pot of warm water is fine. After thawing, be sure to use it within 24 hours. Click here for more on how to store and thaw breastmilk.