It's not much of a reach when you pay attention to the sound design in the death scene and notice that Padme's heart weakens as Anakin strengthens, and Padme's stops just after Vader takes his first breath.Saw something today that might make sense....
I love ROTS and it really gets better with age. But I still can't forgive them for letting Padme die of a broken heart while is medically fine.
Someone pointed out that earlier in the movie Palpatine talks about the unnatural abilities of the Force. And that perhaps, realizing that Padme was the only thing still connecting Anakin to the Light, he used the Force to kill her/drain her life force/whatever you want to call it, in order for there to be nothing left for Anakin and committing him to becoming Vader.
It might be a reach, but as far as head-cannon goes, it works for me.
Also; how else could Palpatine be so sure she's even dead? She was already gone and still alive by the time he got to Mustafaar.
Honestly I'm just a little curious as to the official story of how her body even got to Naboo. Maybe the claim is that the droids took her home? Or they called Bail to come get her? Or Obi-Wan dropper her off then promptly disappeared?