Can you microwave breast milk?

A microwave heats liquid unevenly, so a bottle can hold pockets well above body temperature while the outside of the bottle still feels cool to your wrist. Those hot spots have caused mouth and throat burns in infants. Heating also degrades some of the immune components in human milk, though the burn risk is the reason the guidance is absolute. CDC and FDA both say to warm breast milk in warm running water or a bowl of warm water instead, and note that milk does not need to be warmed at all — cold or room temperature is fine.

What goes wrong

• Localised hot spots scald an infant mouth and throat
• The bottle exterior gives no warning because it stays cool
• Heating destroys some antibodies and enzymes in the milk

What to do instead

• Stand the sealed bottle or bag in a bowl of warm water for a few minutes
• Hold it under warm, not hot, running water
• Serve it at room temperature or cold — babies do not require warmed milk

Other "can you microwave" questions

• Can you microwave styrofoam? It depends — Only if the container is labeled microwave-safe, and most takeout foam is not.
• Can you microwave aluminum foil? No — No — foil reflects microwaves and the edges arc, which can start a fire.
• Can you microwave plastic containers? It depends — Only ones labeled microwave-safe — cold-storage tubs are not among them.
• Can you microwave eggs? It depends — Beaten or pricked eggs, yes. A whole egg in its shell will explode.
• Can you microwave Tupperware? It depends — Yes, if that specific piece carries the microwave-safe symbol on its base.
• Can you microwave paper plates? It depends — Plain white paper plates are fine; anything with metallic trim or a foam layer is not.
• Can you microwave metal? No — No — metal reflects microwaves, arcs at edges, and can damage the oven or start a fire.
• Can you microwave takeout containers? It depends — Only if the container is marked microwave-safe — most are not, and metal-handled ones never are.
• Can you microwave cardboard? It depends — Plain dry cardboard is usually fine briefly; anything with glue, staples, wax or foil is not.
• Can you microwave glass? It depends — Yes for ordinary heatproof glass; no for leaded crystal, and never straight from the freezer.
• Can you microwave water? It depends — Yes, but very clean water can superheat and erupt when you move the cup.
• Can you microwave ceramic? It depends — Yes for plain glazed ceramic; no if it has metallic trim or is unglazed and porous.