How does a woman distinguish between menstrual blood and istiḥāḍah if bleeding continues after purification, or is interspersed with periods of dryness, or if the colors become mixed after seeing the white discharge, especially during the postpartum period (nifās) which may extend beyond forty days?

1/ If a woman's habitual purity is marked by both dryness (jufūf) and the white discharge (qaṣṣah) together, it is recommended for her to wait for the white discharge until the end of the chosen prayer time if she only observes dryness. If her habitual purity is marked by dryness alone, she should not wait for the white discharge if she observes it, and vice-versa. Dryness means that the cloth comes out without being colored by blood, or brown or yellow discharge.

2/ Any brown or yellow discharge that appears after dryness or the white discharge has no effect, based on the saying of Umm ʿAṭiyyah: "We did not consider the yellow or brown discharge after purity as anything."

3/ If purity is interrupted and she sees dryness or the white discharge before the completion of her usual period, and then blood returns, she combines the days of bleeding and performs ghusl whenever it stops. So, if her usual period is six days and she becomes pure after the fourth day, she performs ghusl and prays. If the blood returns after one or two days, she refrains from prayer for two days, and anything beyond that is irregular bleeding (istiḥāḍah).

4/ The ruling for post-natal bleeding (nifās) is similar: if she becomes pure before forty days, she performs ghusl and prays. If the blood returns and there is no 15-day break between the two bleeding periods, it is considered nifās until the total duration of bleeding reaches forty days. Anything beyond that is istiḥāḍah, unless it coincides with her usual menstrual period, in which case it is considered menstruation.

5/ Distinguishing between menstrual blood and istiḥāḍah by color, smell, or pain applies to those who are able to make such distinctions. However, for those whose blood cannot be distinguished, they are not required to do so.