Unbasa bin Sa'id bin al-Aas عنبسة بن سعيد بن العاص بن سعيد · Divorce (Kitab Al-Talaq)

Ibn ‘Umar said that he divorced his wife while she was menstruating. ‘Umar mentioned the matter to the Prophet(ﷺ). He (the Prophet) said “Order him, he must take her back and divorce her when she is purified (from menstrual discharge) or she is pregnant.”