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 ʻalayhi wa sallam, is His slave and Messenger.
If this woman observed blood, then she is menstruating, so if she observes purity by either of its indications, dryness or a white discharge, then she must perform Ghusl before praying. If she observes blood again on the seventh day, as mentioned, then she is menstruating again and she must refrain from performing the prayer until the bleeding stops. However, if she sees a yellowish or brownish discharge after the bleeding stops, this is not considered part of the menses unless it comes out during the time period of the regular monthly menses. As for any white discharge during the course of the month, it is a normal vaginal secretion and she is pure according to the most valid opinion. However, the Wudhoo’ is invalidated by it. Please, refer to Fatwa 136790.
In conclusion, the indications of purity observed between two instances of bleeding are actual and the prayer, fasting and other acts of worship performed in this time are valid.
Allaah Knows best.