Board Thread:Naruto Gaiden/@comment-32622248-20170719100834/@comment-25632268-20170728164235

Whitewing9709 wrote: That's also why the host dies when the beast is removed (with the exception of some Uzumaki Clan members because of their huge chakra resevoirs, Kushina probably would've lived if Kurama hadn't stabbed her)

She would survive only if she sealed Kurama inside her again. Which she wanted to do, but she and Minato had no knowledge that it would save her, they were sure Kushina will die anyway.