All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is permissible for a menstruating woman to wash the dead and there is no evidence in the Quran or the Sunnah that prevents it. Besides, we do not know of any scholar who issued a Fatwa stating that the person washing the dead must be in a state of ritual purity or in a state of ablution. Indeed, the matter of menses is not in a woman’s hands so that we can say that it is forbidden for her to do so.
Nonetheless, some scholars of the Salaf (righteous predecessors), like Al-Hassan Al-Basri, Ibn Seereen and some jurists are of the view that it is disliked for a menstruating woman to wash the dead and said that it is desirable for her to avoid washing the dead.
Allaah Knows best.