When should a woman purify herself and begin fasting if light brown or pinkish discharge continues after her usual days of menstruation have ended?

If the menstrual period is seven days and the woman sees purity, then any yellowish or brownish discharge she sees thereafter is not considered menstruation. She must purify her body and clothes from it, and perform ablution for each prayer if the discharge continues. As for fasting, she must fast immediately upon seeing purity, and her fast is valid; there is no need to wait for the yellowish or brownish discharge to cease. However, if she sees blood after performing ghusl (definition), it is considered menstruation as long as it occurs within a timeframe suitable for menstruation, and she must repeat ghusl after it stops. In this case, her fast is not valid.