What is the ruling if a menstruating woman becomes pure before the time of Fajr and makes a Ghusl?
Her fast is correct if she is certain that she has become pure before Fajr. What is important is that she is certain that she has become pure. This is because some women think that they have become clean when in fact they have yet to become clean. This is the reason women used to go with their cotton (which they used to shield the blood) to ‘Aaisha (radi Allahu ‘anha) and show it to her to see if the sign of purity was present, she would say to them,
No do not hasten until you see the white discharge.
So it is a must upon the women to take her time and wait until she is certain that she has become pure. (Her fast is correct) if she became pure and made her intention to fast (before the time of Fajr), even if she didn’t take a Ghusl until after the time of Fajr has already entered. However, it is binding upon her to be preserve her Salaat by hastening to take a Ghusl so she can pray Fajr during its time. It has reached us that some women become pure after the time of Fajr (had entered) and before the time of Fajr (had entered) and instead delay taking a Ghusl until after the sun has fully risen, using the excuse that they (waited) to (have time to) take a “good and more thorough shower” so they could be cleaner. This is incorrect whether in Ramadhaan or outside Ramadhaan. This is because it is obligatory upon her to hasten and take a Ghusl so she can pray on time, so she should take a light shower so she can perform the obligatory prayer. And if she wants to increase her cleanliness (by taking another shower), she can do so after the sun has risen, and there is no problem with that.
Similar to the case of the women who had her menses is that of the one who is in a state of sexual impurity who didn’t take a Ghusl until after Fajr (had entered). There is no problem in this and their fast is correct. Like if a man who was sexual impure and he didn’t take a Ghusl until after the time of Fajr had already entered and was fasting, there is nothing upon him with regards to that. This is because it is confirmed upon the Prophet ﷺ that Fajr came upon him while he was in a state of sexual impurity from his family and he got up and made a Ghusl after the time of Fajr had entered, and Allah knows best.