It was narrated from Ibn 'Umar that he divorced his wife when she was menstruating, but the Messenger of Allah told him to take her back, and divorce her when she was pure (not menstruating).
أَنَّهُ طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَرَدَّهَا عَلَيْهِ رَسُولُ اللَّهِ ﷺ حَتَّى طَلَّقَهَا وَهِيَ طَاهِرٌ