Is it obligatory to wake up before Fajr to ensure ritual purity for one who has not become pure after Isha, and is it obligatory to wake up before sunrise to ensure ritual purity for one who has not become pure after Fajr?

A woman is not obliged to wake up before Fajr to check for purity from menstruation, as that is an unnecessary burden and hardship lifted from the Ummah. Rather, she should check before sleeping and at the times of prayers. Indeed, the daughter of Zayd ibn Thabit disapproved of women who used lamps at night to check for purity. Al-Kharashi said: "She is not required to check for her purity before Fajr, but rather before sleeping and at the time of every prayer." If she doubts whether she saw purity before Fajr or after it, then she should only pray Fajr. She is not required to make up Maghrib and Isha, and her fast for that day is not valid.