It was narrated from 'Aishah that Umm Habibah bint Jahsh used to suffer from Istihadah for seven years. She asked the Prophet (ﷺ) and he said:"That is not menstruation, rather it is a vein. Tell her not to pray for the period of time that her period used to last, then let her perform Ghusl and pray." She used to perform Ghusl for every prayer.
أَخْبَرَنَا أَبُو مُوسَى، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ عَمْرَةَ، عَنْ عَائِشَةَ، أَنَّ ابْنَةَ جَحْشٍ، كَانَتْ تُسْتَحَاضُ سَبْعَ سِنِينَ فَسَأَلَتِ النَّبِيَّ صلى الله عليه وسلم فَقَالَ " لَيْسَتْ بِالْحَيْضَةِ إِنَّمَا هُوَ عِرْقٌ " . فَأَمَرَهَا أَنْ تَتْرُكَ الصَّلاَةَ قَدْرَ أَقْرَائِهَا وَحِيضَتِهَا وَتَغْتَسِلَ وَتُصَلِّيَ فَكَانَتْ تَغْتَسِلُ عِنْدَ كُلِّ صَلاَةٍ .
Nesai
The Book of Menstruation and Istihadah • Hadith 357