There is a girl whose menstrual period usually lasts for ten days. In the previous Ramadan, she started her period as usual. In the ninth day of the period, she did not fast, assuming that she was still menstruating. However, she noticed during the daytime that the bleeding had stopped and that she became pure of menses. She is not certain whether she became pure of the menses before or after Fajr on that day. Should she make up for that day or fast two consecutive months?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

As for this woman who had doubts whether she became pure of her menses before or after Fajr, she had to fast the day on which she became free of menses and then fast another day later. However, she is not required to offer an expiation, even if she did not fast that respective day. 

In his commentary on Sharh Ad-Dardeer li Mukhtasar Khaleel, Ad-Dusooqi, the Maliki scholar, says:

If she (a woman menstruating in Ramadan) doubts whether she became free from menses before or after Fajr, she has to fast that day because there is a possibility that her period ended before Fajr. She is also required to fast another day later because there is a possibility that her period ended after Fajr. According to Al-Majmoo’, it appears that she is not required to offer an expiation if she did not fast that day. Fasting on this day is different from fasting on the day of doubt (last day of Sha‘baan) because the verification of the end of menstruation is more possible.

That being said, the woman in question has to make up the day in which she recognized that she became free of menses. She is not required to fast two consecutive months. She is not required either to make up for any prayers except for the prayers of which she was sure that she was pure of menses. This is because her purity from menses starts at the moment that she recognizes the end of her period, not before that.

Allaah Knows best.