Anas bin Sirin says that once Sayyiduna Ibn Umar (may Allah be pleased with them) divorced his wife while she was in her menstrual period. Sayyiduna Umar (may Allah be pleased with him) mentioned this to the Prophet (peace and blessings be upon him), so he said: "Tell him to take his wife back, and when she becomes pure, then he may divorce her in the period of purity." I asked, "Did you count the divorce that was given during her menstrual period?" He said, "What was the reason for not counting it?"