Is it permissible for a menstruating woman to make up the 9th, 10th, and 11th of Muharram after she becomes pure?

Whoever missed the fast of Ashura does not make it up, because there is no evidence for that, and because the reward is tied to a specific day that has passed. Voluntary acts of worship that are tied to a reason, like the fast of Ashura, expire when their reason expires and are not to be made up. However, whoever was excused - such as a menstruating woman or a sick person - and their intention was to fast that day, they will be rewarded for their intention, as the Prophet, peace and blessings be upon him, said: "If a servant falls ill or travels, what he used to do when he was healthy and resident will be recorded for him."