What is the prescribed method for 'istibra' (seeking abstinence to ascertain purity of the womb) in the case of the oath 'If I become pregnant, you are divorced'?
Chapter on Explicit Divorce and Others
Al-Mughni
Book of Divorce
Primary text
Imam Ahmad, in one narration, stated the wife should not be approached until she menstruates. After she becomes pure from menstruation, he may have intercourse. If her menstruation is delayed, women knowledgeable in such matters should examine her. If they cannot be found or the matter is unclear to them, nine months, the usual duration of pregnancy, should be awaited.
Supporting text
Another narration mentioned by Al-Qadi suggests 'istibra' should be done with three cycles (Quru'), viewing it as the 'istibra' for a free woman, which is one view among Shafi'i scholars. The correct opinion is that one menstrual cycle suffices because the purpose is to know the purity of the womb, which is achieved by one cycle, supported by the Prophet's saying: 'A pregnant woman should not be approached until she gives birth, and a non-pregnant woman until she seeks a period of abstinence by one menstruation' (meaning she ascertains her purity with one menstruation). The proof for this is that the means to ascertain purity is the same for a female slave and a free woman because it is a real matter unaffected by status. Legal waiting periods (Iddah) involve a ritualistic element that cannot be extended by analogy.