Fatima bint Abi Hubaish came to the Prophet ﷺ and said, "O Messenger of Allah ﷺ I get persistent bleeding from the uterus and do not become clean. Shall I give up my prayers?" Messenger of Allah ﷺ replied, "No, because it is from a blood vessel and not the menses. So when your real menses begins give up your prayers and when it has finished wash off the blood (take a bath) and offer your prayers." Hisham (the sub narrator) narrated that his father had also said, (the Prophet ﷺ told her): "Perform ablution for every prayer till the time of the next period comes."
جَاءَتْ فَاطِمَةُ ابْنَةُ أَبِي حُبَيْشٍ إِلَى النَّبِيِّ ﷺ فَقَالَتْ يَا رَسُولَ اللَّهِ إِنِّي امْرَأَةٌ أُسْتَحَاضُ فَلاَ أَطْهُرُ أَفَأَدَعُ الصَّلاَةَ فَقَالَ رَسُولُ اللَّهِ ﷺ لاَ إِنَّمَا ذَلِكِ عِرْقٌ وَلَيْسَ بِحَيْضٍ فَإِذَا أَقْبَلَتْ حَيْضَتُكِ فَدَعِي الصَّلاَةَ وَإِذَا أَدْبَرَتْ فَاغْسِلِي عَنْكِ الدَّمَ ثُمَّ صَلِّي قَالَ وَقَالَ أَبِي ثُمَّ تَوَضَّئِي لِكُلِّ صَلاَةٍ حَتَّى يَجِيءَ ذَلِكَ الْوَقْتُ