Is performing ghusl in the second month considered sufficient for an invalid ghusl in the first month, or does each menstrual period require an independent intention? And is it obligatory to make up only the prayers of the first month, or to repeat ghusl and prayers for all three months?

If a woman performs ghusl incorrectly, missing an obligatory part, or performs ghusl before her menstruation has ceased, her second ghusl suffices for the single impurity.

Ibn Qudamah said: "If two things necessitate ghusl, such as menstruation and janabah (major ritual impurity), or sexual intercourse and ejaculation, and she intends both with her purification, it suffices for both... Similarly, if events that necessitate minor purification accumulate, such as sleep, emission of impurity, and touch, and she intends them with her purification, or intends the removal of impurity, or the permissibility of prayer, it suffices for all."

The prayers of the last two months after the correct ghusl are sufficient. As for the prayers performed after the incorrect ghusl, there is a difference of opinion regarding the obligation of repeating them. However, the more cautious approach is to make them up, which is the view of the majority of scholars.