All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger. Shaykh Ibn 'Uthaymeen said: "Yes, her fasting is valid and these spots are not considered as significant as they are merely from the veins. It was narrated that 'Ali ibn Abi Taalib said that such spots of blood that are like a nose-bleed, are not menstruation."Allaah Knows best. (Source: islam_web) Classified in Siyaam (Fasting) > Matters That Do not Invalidate Saum