There's nudity and a rape scene.
There's some nudity.
Though there's a rape scene (shown, but not that detailed) that seems to have no point other than to make a best friend into a worst enemy (though it's only one of the reasons).
Don't know why they include a scene like that, I know on why she slashed her wrist, okay? No point of showing the reason on why she did it. And please, even Miaka is careful enough of disguising herself in a rough neighborhood and she is NOT THAT smart.
Don't know much though, I stopped watching midway during the series.
Of course, Fushigi Yuugi is not the type of series that its major selling point is beautiful scenes featuring female bodies, it's a 'romantic' type series. That should be your mum's major concern.