Hadith: Stop (praying) and wait for as long as your menstrual period would normally prevent you from praying, and then take a ritual bath

عن عائشة رضي الله عنها أن أم حبيبة بنت جحش شكت إلى رسول الله صلى الله عليه وسلم الدم، فقال: «امكُثِي قَدْرَ ما كانت تَحبِسُكِ حَيْضَتُكِ، ثم اغتَسِلِي». فكانت تغتسل كل صلاة.
[صحيح] - [رواه مسلم]

‘Ā'ishah (may Allah be pleased with her) reported: Umm Habībah bint Jahsh complained to the Messenger (may Allah's peace and blessings be upon him) about blood (which would flow beyond her menstrual period). He said to her: "Stop (praying) and wait for as long as your menstrual period would normally prevent you from praying, and then take a ritual bath." So, she used to take a ritual bath for every prayer.
Sahih/Authentic. - [Muslim]

Explanation

This Hadīth explains the ruling pertaining to a woman who experiences non-menstrual vaginal bleeding. A woman who experiences such a condition should leave prayer for the number of days her menses would normally last, if her menses is regular and takes a certain number of days every month. When this number of days is over and she is still bleeding, she has to pray and fast normally. A woman in the state of Istihādah is the one who incessantly experiences vaginal bleeding.