There is a girl whose menstrual period usually covers 5 days. During Ramadan, she was breaking her fast on the fifth day of her normal period, thinking that her period had not yet expired. However, she realized that she had become pure of menses during the daytime of the fifth day. She is not certain whether her period expired before or after the Fajr time. Shall she only make up the day or should she fast two consecutive months?

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

If a menstruating woman doubts whether her period has ended before or after the Fajr time of a specific day, she has to abstain from whatever invalidates the fast till the end of that day, in addition to fasting one more day later on. This is stated by Al-Kharshi in Sharh Mukhtasar Khaleel and the commentary on Nathm Al-Kafaaf. She does not have to fast two consecutive months in expiation.

Allah knows best.