With kyubbi naruto without kyubbi i d say Kushina uzumaki want to know why ? here s why Kisha survived child birth which makes people very weak and after that she got her bijju extrated which in normal people even if they are totaly ok they die kushina survived even after she gave child birth and now even after those two she still had chakra to surppres kyubbi s chakra that s why i d give it to kushina