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 ‘alayhi wa sallam, is His slave and Messenger.
If the discharged blood was menstruation, as it is clear from the question, and it was discharged during any part of the daytime of Ramadan, at the beginning or the end, then her fasting is invalid. For the woman's fasting to be valid, it is conditioned that she experiences neither menstruation nor post-partum bleeding. Since fasting is invalid in this case, she has to make up for these days of fasting.
Allaah Knows best.