Reference: Fataawa Ramadhaan – Volume 1, Page 345, Fatwa No.292
Fataawa as-Siyaam – Page 131
Question: If a woman purified herself in Ramadhaan before the adhaan of Fajr, is she required to fast?
Response: If the woman’s [menses] blood ceased to flow during the last part of the night [before Fajr] in Ramadhaan, then it is correct for her to take the pre-dawn meal [sahoor] until Fajr time. That is because in this state she is pure [as her menses blood has stopped] and she is [therefore] required to fast, but not to pray until she takes the ritual bath of purification, and likewise it is not correct for her to engage in sexual intercourse until she has taken the ritual bath of purification as Allaah (Subhaanahu wa Ta’aala) says: