Warming bottles

preggersINschool25

I know that you shouldn't warm BM bottles the microwave because it kills the antibodies and create hot spots.

But if you warm it in water, how does that keep it from killing the antibodies?

If you do microwave the bottle and there are hot spots, wouldn't swirling it eliminate those hot spots?

How important is it that the bottle is warm anyways?  I mean if your baby will take it cold is that a problem?  My mom seems to think that a cold bottle isn't good for LO tummy.  Is she right?