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.
This issue is a matter of difference of opinion among the scholars and in our view, it is permissible for a husband to divorce his wife after she becomes pure from menses and before she performs Ghusl; this is the opinion of the Shaafi’i school of jurisprudence and the correct opinion in the Hanbali school of jurisprudence. An-Nawawi from the Shaafi’i school of jurisprudence said: “If the bleeding of menses stops, there are only two things that are valid before Ghusl: fasting and divorce…” Besides, Al-Mardaawi from the Hanbali school of jurisprudence, said: “If the bleeding stops, fasting and divorce become permissible, and this is the correct opinion in our school.” Therefore, if a husband divorces his wife in this situation, he is not sinful and his divorce takes place.
Moreover, even if he divorces her while she is in menses, his divorce takes place according to the most preponderant opinion and this is the view of the majority of the jurists . But he is sinful by divorcing her while she is in her menses, because divorcing one’s wife in menses is a Bid’i divorce [i.e. it is innovated and not according to the Sunnah] and this divorce is forbidden. For more benefit, please refer to Fatwa 84647.
Allaah Knows best.