What is the ruling for a woman experiencing bleeding that exceeds her usual menstrual period duration?
Chapter on Menstruation
Al-Mughni
Book of Purification
Primary text
If a woman sees blood beyond the length of her usual habit (ada), she is considered a woman experiencing istihada (abnormal, non-menstrual bleeding). Her menstruation is limited only to the duration of her established habit. In subsequent months, she must cease observing religious duties only for the duration of her former habit. This ruling is universally held by those who recognize the validity of establishing a habit. For example, if her habit is three days and she sees five days of blood in one month, she must revert to observing three days of abstinence in all future months. This view is held by Abu Hanifa.
Supporting text
Al-Shafi'i holds that she must abstain for five days in every subsequent month. This divergence is based on whether a single instance of extended bleeding is sufficient to establish a new habit. If she sees five days in two separate months, the matter depends on the recognized differing opinions regarding what establishes a habit. However, if she sees five days over three months, her habit transfers to five days without dispute among scholars.