All statements dealing with this topic have no sound backing. If a woman has a customary length of time for her menses, she should according to it. Umm Salamah asked the Prophet about a woman with a prolonged flow of blood. If she has no customary period to go by, then she can try to distinguish between the different types of blood. This practice is based on the previously quoted hadith of Fatimah bint Abu Hubaish, which states that menstrual blood is distinguishable and well-known to women.
All scholars agree that there is no minmum or maximum time limit between two menstrual periods.
Some say that the latter period is fifteen days, while others say it is three days. Post-Childbirth bleeding Such bleeding occurs after the birth of a child, regardless if the child survived the birth or not. This type of bleeding has no minimum duration, for it could stop right after the birth, or there could even be no blood. Therefore, her confinement would end and she would be obliged to fast, pray, and so on. The maximum duration is forty days.