>>215367926

I always interpreted it as that she and Anakin had become psychically linked and his betrayal of her and subsequent triggered some sort of backlash that induced multiple organ failure.

Also, if you think about it, Padme had basically spent the last few days watching her entire life's work come crashing down. Everything she had ever sweat, fought, and bled for was in vain. She already didn't have that much to live for, Anakin rejecting her and then trying to kill her was the final straw.