What is the ruling for a woman experiencing an irregular and non-sequenced menstrual variation?
Chapter on Menstruation
Al-Mughni
Book of Purification
Primary text
If the variation in menstruation length is without sequence, such as three days one month, five the next, and four the third, and this pattern cannot be fixed or customarily relied upon, she must observe the minimum duration experienced in any month, which is three days, provided there is no shorter duration confirmed. Following this minimum, she performs ghusl.
Supporting text
Ibn Aqil mentioned a secondary narration within the school of thought suggesting she should observe the maximum duration of her cycle each month, similar to a woman who has forgotten her number of days. This view is deemed incorrect because it mandates abstaining from prayer for two days that are certainly obligatory upon her in some months, thus commanding the abandonment of a certainly obligatory act, which is impermissible. Obligatory prayer is not waived by doubt, unlike the case of the woman who forgets a specific prayer, where the default ruling is continued impurity and cessation of prayer.