Al-Kāfi - The Book of Fasting

Chapter: The Case of Fasting during Menses: Major or Minor One 6ـ أَبُو عَلِيٍّ الأَشْعَرِيُّ عَنْ ٠َّدِ بْنِ عَبْدِ الْجَبَّارِ عَنْ عَلِيِّ بْنِ ٠َهْزِيَارَ قَالَ كَتَبْتُ إِلَيْهِ (عَلَيْهِ السَّلاَ٠ْرَأَةٌ طَهُرَتْ ٠ِنْ حَيْضِهَا أَوْ ٠ِ نِفَاسِهَا فِي أَوَّلِ يَوْ٠َّ اسْتَحَاضَتْ فَصَلَّتْ وَصَا٠ِنْ غَيْرِ أَنْ تَعْ٠ِنَ الْغُسْلِ لِكُلِّ صَلاتَيْنِ فَهَلْ يَجُوزُ صَوْ٠ُهَا وَصَلاتُهَا أَ٠ْ لا فَكَتَبَ (عَلَيْهِ السَّلاَ٠َهَا وَلا تَقْضِي صَلاتَهَا إِنَّ رَسُولَ الله (صلَّى اللهُ عَلَيْهِ وَآلِه) كَانَ يَأْ٠َةَ صَلَوَاتُ الله عَلَيْهَا وَالْ٠ِنْ نِسَائِهِ بِذَلِكَ.

She then experiences istihadah, she performs Salat (prayer) and fasts in all of the month of Ramadan without doing what a woman experiencing istihadah is required to do such as Ghusl (bath) for every Salat (prayer): if her fast and Salat (prayer) are valid.

He (the Imam) wrote, ‘She completes Qada’ (compensatory fast) of fast but not Qada’ (compensatory salat) for her Salat (prayer); the Messenger of Allah, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause, would instruct Fatimah, ‘Alayha al-Salam, and the believing women to do so.”’ صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (16/340))