Salim bin Abdullah (may Allah have mercy on him) said that Sayyiduna Abdullah bin Umar (may Allah be pleased with him) said: I divorced my wife while she was menstruating. Sayyiduna Umar (may Allah be pleased with him) mentioned it before the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) became angry and said: "Let him take her back and keep her until the next menstruation. If he intends to divorce, let him divorce her after purity from that menstruation, before having intercourse. This is the period of divorce in which Allah has commanded divorce." Sayyiduna Abdullah bin Umar (may Allah be pleased with him) had given one divorce, which was counted, and at the command of the Messenger of Allah (peace and blessings be upon him) Sayyiduna Abdullah bin Umar (may Allah be pleased with him) took her back.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 14912