The World Federation One Stop Fiqh

Ruling 489

If a mubtadiʾah, muḍṭaribah, nāsiyah, or a woman with a habit of duration experiences bleeding and the blood has the attributes of ḥayḍ, or if she is certain that her bleeding will last for three days, she must refrain from engaging in ritual acts of worship. In the event that she realises afterwards that it was not ḥayḍ, she must make up the ritual acts of worship that she did not perform.