Is it obligatory to make up the entire month of Ramadan every year, or to fast only 8 days, in the event that a fasting woman does not remember the number of days she was not in a state of ritual purity due to masturbating while fasting?

Whoever has been negligent in prayers, the number of which they do not know, must repent to Allah, then make up what they predominantly believe they missed. They should pray each day, in addition to the five obligatory prayers, as much as they can until they are certain their obligation has been fulfilled. They should limit their make-up prayers to the obligatory ones, not the supererogatory ones. Prayers missed due to menstruation are not to be made up.

This cautionary approach applies to making up missed fasts of unknown number, whether they were missed intentionally or out of ignorance, or due to invalidating the fast by masturbation, or due to menstruation. If the number can be ascertained, then so be it. Otherwise, one must make up what they predominantly believe to be sufficient. It is not permissible to delay making up missed fasts without a valid excuse until the next Ramadan arrives. If this happens, one must feed a poor person for each day in addition to making up the fast.

Sincere repentance is obligatory for the practice of masturbation. Masturbation invalidates the fast and necessitates making up the fast if it results in the emission of semen. It also necessitates a ritual bath (ghusl) from major ritual impurity; otherwise, the prayer will not be valid.