The ruling on the return of blood at the beginning of Ramadan after it has stopped

Question:
What if a woman’s usual pattern is that her period ended at the end of Sha'ban and then it returned to her at the beginning of Ramadan, for example? Is that considered menstruation?

Answer:
If the blood returns like the usual menstrual blood, and she recognizes it, she considers it menstruation, even if there are only a few days between it and the first period, because the period may come earlier than its expected time, and it may be delayed. It is considered menstruation according to the correct view. However, some scholars say that the minimum period of purity between two periods is thirteen days, but the correct view is that there is no minimum limit for the period of purity.