Reference: Fataawa Ramadhaan – Volume 1, Page 346, Fatwa No.294
Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-`Ilmiyyah wal-Iftaa. – Fatwa No.13507
Question: I have a maternal aunt (mother’s sister) who purified herself [from the completion of her menses] before the Fajr time in Ramadhaan and so fasted that day. She later stood to do her Zhuhr prayer and saw yellow discharge, so is her fast [for that day] valid?
Response: If she purified herself before Fajr time and fasted, then her fast is valid, and the yellow discharge has no effect [on her fast] after she had completed her period and purified herself. This is based upon the statement of Umm ‘Atiyyah (radhi-yAllaahu ‘anhaa) who said:
And with Allaah lies all the success, and may Allaah send prayers and salutations upon our Prophet Muhammad (sal-Allaahu `alayhi wa sallam) and his family and his companions.