Ruling on a woman whose menstruation begins at the time of breaking the fast

Question:
A woman fasted for one day, and after breaking her fast with dates and water, but before the Maghrib prayer, her monthly period began. Is her fast for that day valid, or must she make it up?

Answer:
Yes, yes. If she did not see the blood until after sunset, after she had broken her fast, even if it was only with water—the point is after sunset—then her fast is valid. Even if her period began before she prayed Maghrib, as long as the sun had set and her period had not yet started—no blood had come out of her—her fast is valid.