If it recurs three times, then it is menstruation, and she makes up whatever became obligatory during it. If it exceeds its maximum duration, then she is experiencing irregular bleeding. Thus, if some of her blood is red and some of it is black, …

His statement, “If it recurs three times, then it is menstruation,” is as in the preceding example. Her established cycle is therefore ten days. But what should she do regarding the period between the day and night and the tenth day, since she had been praying and fasting during it, only for it to become clear that these were days of menstruation?

It is said: as for the prayer, even though it was not valid from her, she does not make it up, because prayer is not obligatory upon a menstruating woman, nor is she sinful for performing it, since she performed it as an act of worship to Allah and as a precaution.

She must make up the fast, because it has become clear that she fasted on days of menstruation, and fasting is not valid during menstruation—assuming that this occurred in Ramadan.

His statement, “and she makes up whatever became obligatory during it,” means: every act of worship that is obligatory upon a menstruating woman and is not valid from her while she is menstruating must be made up, as in the preceding example. This is a general rule.

If it is supposed that this menstruation did not recur three times with the same number of days—that is, she bled for ten days in the first month, eight in the second, and six in the third—then the six days alone are menstruation. Thus, in the fourth month, if the eight days recur three times, her established cycle becomes eight days; and in the fifth month, if the ten days recur three times, her established cycle becomes ten days. Whatever recurs three times is menstruation.

His statement, “If it exceeds its maximum duration, then she is experiencing irregular bleeding”: “exceeds” means goes beyond; “its maximum duration” means the maximum duration of menstruation, which is fifteen days. “Then she is experiencing irregular bleeding” applies whether she is a woman menstruating for the first time or one with an established cycle.

An example of a woman menstruating for the first time is a woman whose menstrual bleeding comes for the first time and continues with her