Is the validity of the fast contingent upon the cessation of menstrual blood only, or upon the cessation of blood and the performance of ghusl?

If a woman's menstrual bleeding stops before dawn, even for a moment, she is obligated to abstain from food and drink and to fast that day. Her fast is valid even if dawn breaks and she has not yet performed ghusl (ritual bath), because ghusl from menstruation or janabah (major ritual impurity) is not a condition for the validity of the fast. She can perform ghusl afterwards, but it is not permissible for her to delay ghusl until the time for Fajr prayer has passed.