"That is not menstruation, rather it is a vein. Tell her not to pray for the amount of time that her period used to last, then let her perform Ghusl and pray.' She used to perform Ghusl for every prayer.  

أَنَّ أُمَّ حَبِيبَةَ بِنْتَ جَحْشٍ كَانَتْ تُسْتَحَاضُ سَبْعَ سِنِينَ فَسَأَلَتِ النَّبِيَّ ﷺ فَقَالَ لَيْسَتْ بِالْحَيْضَةِ إِنَّمَا هُوَ عِرْقٌ فَأَمَرَهَا أَنْ تَتْرُكَ الصَّلاَةَ قَدْرَ أَقْرَائِهَا وَحَيْضَتِهَا وَتَغْتَسِلَ وَتُصَلِّيَ فَكَانَتْ تَغْتَسِلُ عِنْدَ كُلِّ صَلاَةٍ  

[Machine] Um Habiba, the daughter of Jahsh, experienced istihada (irregular bleeding) for seven years. She was the wife of Abdur Rahman ibn Awf. So she asked the Messenger of Allah ﷺ about this. The Messenger of Allah ﷺ said, "Indeed, this is a vein and not menstruation. So perform ablution and pray." Accordingly, she would perform ablution before every prayer.  

أَنَّ أُمَّ حَبِيبَةَ بِنْتَ جَحْشٍ اسْتُحِيضَتْ سَبْعَ سِنِينَ وَكَانَتْ امْرَأَةَ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ فَسَأَلَتْ رَسُولَ اللهِ ﷺ عَنْ ذَلِكَ؟ فَقَالَ رَسُولُ اللهِ ﷺ إِنَّمَا هَذَا عِرْقٌ وَلَيْسَتْ بِحَيْضَةٍ فَاغْتَسِلِي وَصَلِّي قَالَ فَكَانَتْ تَغْتَسِلُ عِنْدَ كُلِّ صَلَاةٍ  

"That is not menstruation, rather it is a vein. Tell her not to pray for the amount of time that her period used to last, then let her perform Ghusl and pray.' She used to perform Ghusl for every prayer. (Using translation from Nasāʾī 210)  

أَنَّ أُمَّ حَبِيبَةَ بِنْتَ جَحْشٍ كَانَتْ تُسْتَحَاضُ سَبْعَ سِنِينَ فَسَأَلْتِ النَّبِيَّ ﷺ؟ فَقَالَ «لَيْسَتْ بِالْحَيْضَةِ إِنَّمَا هُوَ عِرْقٌ فَأَمَرَهَا أَنْ تَتْرُكَ الصَّلَاةَ قَدْرَ أَقْرَائِهَا وَحَيْضَتِهَا وَتَغْتَسِلَ وَتُصَلِّي فَكَانَتْ تَغْتَسِلُ عِنْدَ كُلِّ صَلَاةٍ»