Sunan an Nasai
The Book of Menstruation and Istihadah
Hadith #40
3.40
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنِي سُفْيَانُ، قَالَ حَدَّثَنِي مَنْصُورٌ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُدْنِي إِلَىَّ رَأْسَهُ وَهُوَ مُعْتَكِفٌ فَأَغْسِلُهُ وَأَنَا حَائِضٌ .
It was narrated that 'Aishah said:"The Prophet (ﷺ) would put his head out while he was performing I'tikaf and I would wash it, while I was menstruating