Is the brownish drop of blood that appears a week after the end of menstruation considered menstruation, and what is the ruling on prayer and fasting in this case?

Brown spots are considered "kudrah" (brownish discharge), and are not considered menstruation after the cessation of the menstrual period and seeing the sign of purity, unless they occur during the time of menstruation. If the spots resemble menstrual blood and appear during the possible time (of menstruation), then it is menstruation with all its rulings. However, if the blood appears outside the possible time (of menstruation), or if the "kudrah" occurs outside the accustomed time (of menstruation), then its ruling is that of "fasad" blood (irregular bleeding).