A questioner says that ever since she reached puberty and started fasting in the month of Ramadan, she has not made up for the days that she did not fast because of menstruation. What should she do now as she does not know the number of days that she missed?
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 'alyhi wa sallam, is His slave and Messenger.
Shaykh Ibn ‘Uthaymeen said: "It grieves us to know that this is done by Muslim women as this happens either out of ignorance or negligence and in both cases, it is a disaster. The remedy for ignorance is knowledge and asking, while the remedy for negligence is to fear Allah The Almighty and His punishment and hasten to do what pleases Him. This woman should repent and ask Allah The Almighty for forgiveness. She should estimate the number of days that she missed as much as she can and make up for them so that she would free herself from liability and we hope that Allah The Almighty will accept her repentance."
Allah Knows best.