Al-Istihadah (bleeding in between the periods is from a blood vessel)
حَدَّثَنَا إِبْرَاهِيمُ بْنُ الْمُنْذِرِ، قَالَ حَدَّثَنَا مَعْنٌ، قَالَ حَدَّثَنِي ابْنُ أَبِي ذِئْبٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ، وَعَنْ عَمْرَةَ، عَنْ عَائِشَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّ أُمَّ حَبِيبَةَ اسْتُحِيضَتْ سَبْعَ سِنِينَ، فَسَأَلَتْ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنْ ذَلِكَ، فَأَمَرَهَا أَنْ تَغْتَسِلَ فَقَالَ " هَذَا عِرْقٌ ". فَكَانَتْ تَغْتَسِلُ لِكُلِّ صَلاَةٍ.
Narrated `Aisha: (the wife of the Prophet) Um Habiba got bleeding in between the periods for seven years. She asked Allah's Messenger (ﷺ) about it. He ordered her to take a bath (after the termination of actual periods) and added that it was (from) a blood vessel. So she used to take a bath for every prayer.