What is required of a woman who used to believe that purification from menstruation was ghusl, and she would delay ghusl to ensure purity, and she only made up the last two prayers after its cessation, and she did not make up the prayer she missed on the first day of menstruation due to her ignorance?

If a woman sees the sign of purity by one of its two indications, she must hasten to perform ghusl (ritual bath) and pray. However, if she doubts the occurrence of purity, the default is that menstruation persists, and there is no blame on her for delaying the ghusl.

If she delays ghusl despite being certain of purity, she must make up the missed prayers, and she must ascertain their number to make them up.

As for the prayer during whose time she started menstruating, the preponderant opinion is that she is not required to make it up.