Urwah ibn az-Zubayr said that Fatimah daughter of AbuHubaysh narrated to him that she asked the Messenger of Allah ﷺ and complained to him about the flowing of (her) blood. The Messenger of Allah ﷺ said to her: That is only (due to) a vein: look, when your menstruation comes, do not pray; and when your menstruation ends, wash yourself and then offer prayer during the period from one menstruation to another. (Using translation from Abū Dāʾūd 280)  

أَنَّهَا أَتَتْ رَسُولَ اللهِ ﷺ فَشَكَتْ إِلَيْهِ الدَّمَ فَقَالَ رَسُولُ اللهِ ﷺ إِنَّمَا ذَلِكَ عِرْقٌ فَانْظُرِي إِذَا أَتَى قُرْؤُكِ فَلَا تُصَلِّي فَإِذَا مَرَّ الْقُرْءُ فَتَطَهَّرِي ثُمَّ صَلِّي مَا بَيْنَ الْقُرْءِ إِلَى الْقُرْءِ  

[Machine] My aunt Fatimah bint Abi Hubaysh told me that she came to Aisha and said to her, "O Mother of the Believers, I have feared that I would not have a share in Islam and that I would be from the people of the Fire, so I stay as long as Allah wills during my monthly period, and I do not pray to Allah during it." Aisha said to her, "Sit and wait until the Prophet ﷺ comes." So when the Prophet ﷺ came, she said, "O Messenger of Allah, this is Fatimah bint Abi Hubaysh, she fears that she would not have a share in Islam and that she would be from the people of the Fire, so she stays as long as Allah wills during her monthly period and does not pray to Allah during it." He said to her, "Tell Fatimah bint Abi Hubaysh to count the number of days of her period every month, then she should perform ghusl (ritual bath), apply perfume, seek forgiveness, and cleanse herself. Then she should purify herself before each prayer and pray, for indeed, that (abstaining from prayer during menstruation) is a rukhsah (concession) from the Shaytan, or a vein that has been severed, or an illness that has afflicted her."  

حَدَّثَتْنِي خَالَتِي فَاطِمَةُ بِنْتُ أَبِي حُبَيْشٍ قَالَتْ أَتَيْتُ عَائِشَةَ فَقُلْتُ لَهَا يَا أُمَّ الْمُؤْمِنِينَ قَدْ خَشِيتُ أَنْ لَا يَكُونَ لِي حَظٌّ فِي الْإِسْلَامِ وَأَنْ أَكُونَ مِنْ أَهْلِ النَّارِ أَمْكُثُ مَا شَاءَ اللهُ مِنْ يَوْمِ أُسْتَحَاضُ فَلَا أُصَلِّي لِلَّهِ ﷻ صَلَاةً قَالَتْ اجْلِسِي حَتَّى يَجِيءَ النَّبِيُّ ﷺ فَلَمَّا جَاءَ النَّبِيُّ ﷺ قَالَتْ يَا رَسُولَ اللهِ هَذِهِ فَاطِمَةُ بِنْتُ أَبِي حُبَيْشٍ تَخْشَى أَنْ لَا يَكُونَ لَهَا حَظٌّ فِي الْإِسْلَامِ وَأَنْ تَكُونَ مِنْ أَهْلِ النَّارِ تَمْكُثُ مَا شَاءَ اللهُ مِنْ يَوْمِ تُسْتَحَاضُفَلَا تُصَلِّي لِلَّهِ ﷻ فِيهِ صَلَاةً فَقَالَ مُرِي فَاطِمَةَ بِنْتَ أَبِي حُبَيْشٍ فَلْتُمْسِكْ كُلَّ شَهْرٍ عَدَدَ أَيَّامِ أَقْرَائِهَا ثُمَّ تَغْتَسِلُ وَتَحْتَشِي وَتَسْتَثْفِرُ وَتَنَظَّفُ ثُمَّ تَطَهَّرُ عِنْدَ كُلِّ صَلَاةٍ وَتُصَلِّي فَإِنَّمَا ذَلِكَ رَكْضَةٌ مِنَ الشَّيْطَانِ أَوْ عِرْقٌ انْقَطَعَ أَوْ دَاءٌ عَرَضَ لَهَا