What is the ruling on repeatedly performing ghusl due to uncertainty in determining purity from menstruation, what are the signs of purity that should be relied upon, how should one deal with blood, kudra (dirty discharge), or sufra (yellow discharge) after seeing dryness, and do the rulings of purity differ based on the day dryness is observed?

A woman recognizes her purity by two signs: dryness (al-jufūf) or the white discharge (al-qaṣṣah al-bayḍāʾ). The recognized dryness is when a piece of cloth is inserted into the vagina and comes out clean. At that point, ghusl (definition) (ritual bath) becomes immediately obligatory, and the woman should not delay. If she sees a yellowish or brownish discharge after purity, it is not considered menstruation unless it occurs during her usual menstrual period. However, if she sees blood after purity and having performed ghusl, it is considered menstruation as long as the recurring blood appears within the possible time frame of menstruation, and she must perform ghusl again after it stops.

The difference between menstruation (ḥayḍ) and abnormal uterine bleeding (istiḥāḍah) is that if the blood exceeds fifteen days, it is istiḥāḍah. Before that, all blood is considered ḥayḍ. If she is experiencing istiḥāḍah and has a previous habit (regular period), she should refer to it. Otherwise, she should distinguish by characteristics (black color, odor, thickness, pain). Scarcity or intermittency of blood is not considered a sign of istiḥāḍah.