For if her waiting period were one month and she claimed that it had ended, that would be unlikely; she would therefore need evidence.

It is conceivable for a woman to menstruate three times within one month, as follows: she menstruates for one day and one night, then remains pure for thirteen days, making fourteen days of the month elapsed. She then menstruates for one day and one night, leaving, at that point, certainly fourteen days—or fifteen days. She then remains pure for thirteen days, leaving one or two days, after which she menstruates for one day and one night for the third menstrual period, and her waiting period is complete. However, this is exceedingly rare.

If a woman claims that her waiting period has ended through menstruation, and this is within a customary time frame, her statement is accepted. Thus, if she claims that her waiting period following divorce ended through menstruation after two and a half months, her statement is accepted without evidence, because Allah has entrusted women with reporting their own cycles. He says:

“Divorced women shall wait by themselves for three menstrual periods; and it is not lawful for them to conceal what Allah has created in their wombs, if they believe in Allah and the Last Day.” [al-Baqarah 2:228]

But if a divorced woman claims that her waiting period ended after twenty-eight days, her claim is rejected and not heard, even if she is among the most truthful of women, because this is impossible. Once we have established the principles that the minimum menstrual period is one day and one night, and that the minimum interval of purity between two menstrual periods is thirteen days, it cannot be completed in twenty-eight days.

If she claims, after the passage of one month—that is, twenty-nine to thirty days—that her waiting period has ended, then her claim is heard; that is, the judge gives it consideration.