Reference: Fataawa as-Siyaam libni Jibreen – Page 132, Fatwa No.158
Question: If a woman purifies herself after having ended her menses during the day, then must she abstain from all that breaks the fast for the rest of the day?
Response: If a woman purified herself after having ended her menses or postpartum bleeding during the day, then she must abstain from all that breaks the fast for the rest of the day and then also make up that day [in fasting]. Indeed her abstaining is for the sanctity of the month and her having to make up that day [in fasting] is because she has not completed the fasts, as fasting has been made obligatory for the [entire] month, and because whoever fasts half the day is not considered to have fasted [that day at all].
