No. Please do not microwave formula or breast milk as it heats unevenly and puts the child at risk for burns.
Use a bottle warmer or run the bottle under a warm tap until you reach the desired temperature. Mix the bottle well to ensure that there are not pockets of milk that are too hot. There is no perfect temperature for reheated milk as long as it is not too hot. If you are measuring, stay below 100 degrees. Often babies will be content as long as there is no chill to the milk.
Reviewed by Dr. Sara Connolly, August 2019