Ghusl for Menstruation and Postpartum
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 21
وَ كَانَ بَعْضُ نِسَاءِ اَلنَّبِيِّ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ تُرَجِّلُ شَعْرَهَا وَ تَغْسِلُ رَأْسَهَا وَ هِيَ حَائِضٌ.
Some of the wives of the Prophet صلى الله عليه وعلى آله وسلم used to comb their hair and wash their heads while they were menstruating.
- Ṣaḥīḥ al-Faqīh