What is the ruling concerning blood that was discharged at intermittent intervals and with unusual characteristics, knowing that the menstrual cycle is regular?

The blood that appeared six days after the menstrual period is not considered menstruation, because a minimum of fifteen days is required for the cessation of menstruation between two periods. This blood is irregular bleeding (istihada), during which a woman is permitted to perform acts of worship and engage in marital relations, provided that the first menstrual period has completed its days and its bleeding has ceased.

As for the blood that appeared during the usual time of menstruation, it is menstrual blood. The reasons mentioned for it not being menstruation are not valid, as the period of purity occurs between two menstrual cycles, not between irregular bleeding (istihada) and menstruation. The appearance of blood without pain has no bearing on whether it is menstrual blood.