Is it permissible to pray, fast, and engage in intercourse during the days of pre-menstrual spotting (al-kudrah) that precede menstruation? And is expiation (kaffarah) obligatory if intercourse occurs during these days or on the fourth day of menstruation after seeing something like purity, followed by the appearance of spotting?

Yellow or brownish discharge (Ṣufrah and Kudrah) before menstruation, if not accompanied by blood, is not considered menstruation. However, if it is mixed with blood, it is considered menstruation if it is possible for it to be menstrual blood. Sexual intercourse with the husband during the days of brownish discharge preceding menstruation is permissible because it is not considered menstruation. Performing ghusl (definition) (ritual bath) after seeing the signs of purity is obligatory, and sexual intercourse with the husband after ghusl is permissible. Brownish discharge that returns after purity during the days of one's regular period is considered menstruation.