Sahih al-Bukhari 2037
Sahih al-Bukhari · Book 33: Retiring to a Mosque for Remembrance of Allah (I'tikaf) · I'tikaf of a woman who has bleeding in between her periods
Narrated `Aisha:
حَدَّثَنَا قُتَيْبَةُ ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ ، عَنْ خَالِدٍ ، عَنْ عِكْرِمَةَ ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتِ اعْتَكَفَتْ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم امْرَأَةٌ مِنْ أَزْوَاجِهِ مُسْتَحَاضَةٌ، فَكَانَتْ تَرَى الْحُمْرَةَ وَالصُّفْرَةَ، فَرُبَّمَا وَضَعْنَا الطَّسْتَ تَحْتَهَا وَهْىَ تُصَلِّي.
One of the wives of Allah's Messenger (ﷺ) practiced I`tikaf with him while she ad bleeding in between her periods and she would see red (blood) or yellowish traces, and sometimes we put a tray beneath her when she offered the prayer.