Chapter on Menstruation, Istihada (abnormal bleeding), and Nifas (postpartum bleeding)

Narrated by Ahmad ibn al-Hasan, from Amr ibn Sa’id, from Musaddiq ibn Sadaqa, from Ammar al-Sabati: Abu Abdillah عليه السلام was asked regarding a woman who is menstruating at the time of dawn in the month of Ramadan. Then, after sunrise, she becomes pure and has already eaten, and she performs the Dhuhr and Asr prayers. How should she handle that day in which she became pure? Imam عليه السلام said: "She should fast but it will not be counted (as valid)."