Do brown discharges and sometimes blood that come down periodically after weaning, which are not accompanied by menstrual pain and whose exact timing is not remembered, invalidate prayer and fasting?

Brownish discharge (kudra) is considered menstruation if it occurs during the usual time of menstruation and does not exceed fifteen days. The proof for this is the hadith (definition) of Umm Atiyyah, who said that they (the women) "did not consider kudra (brownish discharge) and sufra (yellowish discharge) to be anything after ritual purity." Based on this, brownish discharge during the accustomed period of menstruation is considered menses. One must refrain from prayer and fasting until purity is achieved, or until the accustomed duration of menstruation ends, provided it does not exceed 15 days. After achieving purity, one must make up the days of fasting but not the prayers.