What is the ruling on fasting and praying on the fifth day if the bleeding stops at its end, and what is the ruling on repeating the ritual bath (ghusl) if bleeding resumes after performing ghusl on the fifth day, and how can a woman determine the days of her menstrual cycle, especially if its duration has recently changed?

If a woman sees purity before her customary period ends, she must perform ghusl (definition) and pray. If the blood returns during her customary days, it is considered menstruation. Whenever the blood stops and she observes one of the two signs of purity (complete dryness or the white discharge), she must perform ghusl and pray immediately, and it is not permissible to delay it. If her customary period settles on five days, she must perform ghusl after that and pray, and her customary duration will have changed.