I asked Ibn ʿUmar,"(What is said regarding) a man divorces his wife during her period?" He said, "Do you know Ibn ʿUmar? Ibn ʿUmar divorced his wife while she was menstruating. ʿUmar then went to the Prophet ﷺ and mentioned that to him. The Prophet ﷺ ordered him to take her back and when she became clean, he could divorce her if he wanted." I asked (Ibn ʿUmar), "Was that divorce counted as one legal divorce?" He said, "If one becomes helpless and foolish (will he be excused? Of course not). "
قُلْتُ لاِبْنِ عُمَرَ رَجُلٌ طَلَّقَ امْرَأَتَهُ وَهْىَ حَائِضٌ فَقَالَ تَعْرِفُ ابْنَ عُمَرَ إِنَّ ابْنَ عُمَرَ طَلَّقَ امْرَأَتَهُ وَهْىَ حَائِضٌ فَأَتَى عُمَرُ النَّبِيَّ ﷺ فَذَكَرَ ذَلِكَ لَهُ فَأَمَرَهُ أَنْ يُرَاجِعَهَا فَإِذَا طَهُرَتْ فَأَرَادَ أَنْ يُطَلِّقَهَا فَلْيُطَلِّقْهَا قُلْتُ فَهَلْ عَدَّ ذَلِكَ طَلاَقًا قَالَ أَرَأَيْتَ إِنْ عَجَزَ وَاسْتَحْمَقَ