A woman observed fasting during menstruation, out of ignorance, for more than a year and then she came to know the correct ruling. What is the sharia ruling regarding the past years, when she was observing fast during menstruation and did not make up for it? Please advise. Thank you.

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.

Fasting during menstruation is prohibited. When a menstruating woman observes fast, she is guilty and her fast is invalid. If it is an obligatory fast, such as Ramadan, making up for missed days during that month, a vow, expiation for a broken oath, and so on, then she has to make up for the days which she fasted while menstruating.

Accordingly, the days which she fasted during menstruation do not absolve her of the obligatory fast. She has to count these days and make up for them, completely. Nevertheless, she is blameless for being ignorant about the Sharee'ah ruling on fasting during menstruation. Also, she has to feed a poor an average meal for every day as expiation, because delaying making up for the missed days of Ramadan until the next Ramadan, without an acceptable excuse, necessitates expiation. Being ignorant of this ruling pardons only the punishment of the Hereafter, but not the expiation.

We adopt the opinion that expiation is due despite ignorance because nowadays knowledge is widespread and such rulings are not unknown unless there is negligence on part of those who are competent for religious assignment. 

Allaah Knows best.