What is incumbent upon me if I am unable to make up the deferred Ramadan fast until Sha’ban due to menstruation throughout the entire month, with Ramadan just around the corner? And what is the expiation (kaffara) obligatory upon me, given my prior knowledge that I did not know menstruation would last a full month? And if I fast for two consecutive months and menstruation occurs during them, what should I do and what is incumbent upon me? And is my fasting valid if I fast, for example, from the second of Shawwal until the thirtieth of the following month?

You are required to make up for the days you missed fasting after it became clear that you were experiencing irregular bleeding (istihada). You are also required to make up for the prayers you missed, assuming you were menstruating. As for the days you did not fast until Ramadan began, you are only required to make them up after Ramadan, and you must feed a poor person for each day you delayed making up the fast, unless you were unaware of the impermissibility of delaying the make-up, in which case no expiation (fidyah) is required. If you knew of the impermissibility of delaying the make-up but were unaware of the permissibility of fasting while bleeding, the matter is subject to consideration, but it is advised to pay the expiation as a precautionary measure.