What is the ruling of Islamic law regarding a husband’s return to his divorced wife, divorced with an undocumented pronouncement, after the expiration of her waiting period, which she calculates as between 35 and 36 days for her menstrual cycle, and what if the husband claims he did not reconcile despite the wife possessing the divorce decree?

If a woman's iddah (definition) (waiting period) after her husband divorcing her expires and he has not taken her back, then she becomes irrevocably separated from him according to Islamic law, whether the divorce was documented in court or not. If the husband claims after the iddah has expired that he took her back during it, then her word is to be accepted unless she confirms his claim, because the default is that there was no raj'ah (revocation of divorce) and that the separation has occurred. The iddah of a divorced woman varies according to her condition: three menstrual cycles for a menstruating woman, three months for a woman past childbearing age or a young girl, and delivery of the baby for a pregnant woman. Regarding recurrent menstruation, if its recurrence can be precisely determined, then it is considered a stable habit.