Ghusl is invalid if performed while menses has not yet ceased completely. Purity is confirmed either by the appearance of a white discharge or complete dryness (no discharge). If Ghusl is performed before confirming purity, then the Ghusl must be repeated for prayers to be valid. However, if a woman becomes certain of her purity before Fajr (even without repeating ghusl), her fast for that day remains valid.