Board Thread:Naruto Discussions/@comment-26431570-20190526171926/@comment-32685487-20190527192925

Yeah Mito and Hashi were already together and married at that point, which is why she was able to go to Kurama and seal him in herself for Hashirama after the fight with Madara concluded. It is also most likely her and Hashirama's child was already born when she made herself into a Jinchuriki.