The World Federation One Stop Fiqh

Ruling 431

If a woman knows that the blood being discharged is not blood from an injury but she is uncertain whether it is the blood of istiḥāḍah, ḥayḍ, or nifās, then in the event that the blood is not legally (sharʿan) ruled as being that of ḥayḍ or nifās, she must act according to the instructions pertaining to istiḥāḍah. In fact, if she doubts whether it is blood of istiḥāḍah or another type of blood, then in the event that it does not have the attributes of other types of blood, based on obligatory precaution, she must consider the blood to be istiḥāḍah.