This is because lunar months stand in for menstrual cycles. Some scholars, however, maintained that her waiting period is one and a half months, on the grounds that a slave-woman’s ʿiddah is half that of a free woman, and the ʿiddah of a free woman who no longer menstruates is three months; accordingly, the menopausal slave-woman would wait one month and a half.

As for a divorcee who used to menstruate but whose menses has now ceased for a reason other than old age, she falls into two categories:

1. She does not know what has stopped her menstruation. Her ʿiddah is one full lunar year: nine months to eliminate the possibility of pregnancy, followed by the menopausal ʿiddah of three months. Imām al-Shāfiʿī said, “This was ʿUmar’s ruling among the Emigrants and the Helpers, and, so far as we know, none of them challenged it.” The purpose of the waiting period is to ascertain that the womb is free of pregnancy; once nine months have passed this becomes clear, after which she observes the menopausal ʿiddah of three months, totalling twelve months—ample time to confirm freedom from both pregnancy and menstruation.

2. She does know the cause of the cessation—such as illness, breastfeeding, or medication that suppresses menstruation. She waits until that impediment ends; if her menses returns, she completes her ʿiddah on the basis of menstrual cycles. If the impediment is removed yet the menses does not return, the correct view is that she waits a full year, like the woman whose menses stopped for an unknown reason. This was the choice of Shaykh al-Islām Ibn Taymiyyah and is one transmitted report from Imām Aḥmad.

As for the woman experiencing istiḥāḍah (persistent non-menstrual bleeding), she too has several cases.

1. If she knows the number and timing of her former regular menses before the istiḥāḍah began, her ʿiddah ends once a span equal to three menstrual periods—calculated according to her previous habit—has elapsed.