What is the ruling regarding a woman who menstruates for 20 to 25 days, whose period comes every 4 months, and whose blood flows continuously without interruption, and this has been her habit since puberty?

The jurists differed on the maximum duration of menstruation. The Hanafis held that its maximum is ten days, while the majority held that its maximum is fifteen days, and anything beyond that is considered istihada (non-menstrual bleeding).

Some scholars, such as Ibn al-Mundhir and Ibn Taymiyyah, are of the view that there is no maximum limit for menstruation, and this is the preponderant opinion. They base this on the generality of the verse: "And they ask you about menstruation. Say, 'It is an adha (a harmful/impure thing),'" so the adha (harm/impurity) is the basis of the ruling.

Accordingly, the menstrual period occurring every four months and lasting from 20 to 25 days is considered menstruation, during which the woman refrains from prayer, fasting, and sexual intercourse.