Must a woman who experiences bleeding due to medication that affected her menstrual cycle, with the bleeding lasting for more than two weeks—given that the doctor considered it menstruation—fast and pray? And is she required to make up for the fasting and prayers she missed due to her cessation of worship?

The blood a woman sees is considered menses if it does not exceed 15 days and nights, and if there was a period of 15 days or more between the cessation of the previous blood and the sight of this blood. If the duration of the blood exceeds 15 days, or if she sees it less than 15 days after the previous menstruation and it cannot be combined with it, then the woman is considered to have irregular bleeding (istihada). A woman experiencing irregular bleeding must take precautions and perform ablution for each prayer after its time has begun.

If the woman has a previous regular habit, the duration of her habit is menses, and anything beyond that is irregular bleeding. If she does not have a habit but can distinguish menstrual blood by its characteristics, then what she distinguishes as such is menses, and anything beyond that is irregular bleeding. If she has neither a habit nor the ability to distinguish, she considers herself menstruating for 6 or 7 days each month.

Fasting performed during the menstrual period is invalid and must be made up. However, fasting during the period of irregular bleeding is valid and does not require making up. Prayers that were omitted because they were mistakenly thought to be during the menstrual period, when they were actually during the period of irregular bleeding, must be made up.