How is the menstrual period determined for a woman whose established habit was five days, but now experiences bleeding, initially black for three days, which then turns red and continuous?
Chapter on Menstruation
Al-Mughni
Book of Purification
Primary text
If precedence is given to the established habit (al-'ada), she sits for five days each month, as she did before the irregular bleeding. If precedence is given to differentiation (at-tamyez), her period is the three days of black blood. However, in the first month, she does not omit prayer for the time exceeding three days, because it is only established that she is experiencing Istihada (abnormal bleeding) once the blood exceeds the maximum duration of a normal menses. Once the blood exceeds the maximum duration in the first month, it is known to be Istihada. Thus, in the second month, she only omits prayer for the duration exceeding the black blood.
Supporting text
If she sees ten days of black blood followed by red and continuous bleeding, those who prioritize habit state that she does not acknowledge anything beyond her established habit until it recurs. Therefore, in the first or first two or three months, her menses is only five days, the duration of her habit. Those who prioritize differentiation state that if the bleeding exceeds the habit duration the first time, she sits for fifteen days in the first month, then performs Ghusl (ritual bath) and prays. In the second month, she observes the duration of the habit, which is the first five days of the month for those prioritizing habit. Those prioritizing differentiation do not require repetition and consider all ten days as menses.