What is the ruling on prayer and fasting when drops of blood and brown and black discharges appear at spaced intervals, given the irregularity of the menstrual cycle?

The maximum duration of menstruation, according to the majority of scholars, is fifteen days, and the minimum is one day and one night. There is no minimum limit for menstruation according to the Malikis and Sheikh Al-Islam Ibn Taymiyyah. The minimum duration of purity (Tuhr) between two menstrual periods is thirteen days according to the Hanbalis.

So, if you see spots of blood during a time that is suitable for menstruation, and the total days of bleeding and purity do not exceed fifteen days, then it is menstruation. As for yellowish or brownish discharge, it is not considered menstruation unless it occurs during the usual period.

If the duration of bleeding exceeds fifteen days, or its total does not reach one day and one night according to the majority, then you are experiencing Istihada (non-menstrual bleeding). In this case, you must purify yourself, perform ablution (Wudu'), and pray.

If you find a time within the prayer period that allows for performing a valid purification, you should pray during that time. If the bleeding covers the entire prayer time, then perform Wudu' after the time for the prayer has begun, and pray the obligatory prayer and any supererogatory prayers you wish with this ablution.