Is fasting valid during the days following the eleventh day of the menstrual cycle, given that the questioner performed ghusl on the tenth day of her cycle, then noticed light-colored discharge on the eleventh day, which one of her friends considered istiḥāḍah (irregular bleeding), and she did not perform ghusl until 4 or 5 days after that?

If a woman has confirmed purity by seeing the white discharge or dryness, she must perform ghusl (ritual bath). The fast of the first day is valid if the blood descended after sunset, and the fast of the second day is valid if the bleeding stopped before dawn and did not return thereafter. Menstruation lasts up to fifteen days, and what occurred is considered menstruation as long as it does not exceed that period. The days of fasting that coincided with menstruation must be made up, but there is no need to make up the prayers. The ghusl is sufficient with the intention of removing the major ritual impurity. If pure days passed without performing ghusl, then the prayers performed before the ghusl must be made up. There is no sin in fasting during menstruation out of forgetfulness or ignorance.