פירוש על דברי הימים ב 29:5

and remove the ‘menstruant’ The Midrash Aggadah (source unknown) states: ‘The corpse’ is not stated here, but ‘the menstruant,’ which is more repugnant than the corpse. It is compared to the uncleanness of the menstruant, because menstrual blood is repugnant.