Is it obligatory to abstain from prayer when discharge resembling menstrual blood, with a different odor, appears after menopause due to age and chemotherapy?

The default is that blood discharged from a woman is menstrual blood unless there is a known reason for its descent. There is no specific age for menopause from menstruation; it may cease and then return, and this returning blood is considered menstruation. The criterion for menopause is the actual cessation of blood, not reaching a specific age, even if the woman is over fifty. Islamic law has linked the rulings of menstruation to the discharge of blood known by its characteristics, whether its color is black or otherwise. If she is unsure due to illness or medication, she should consult a female doctor.