Is it permissible to delay ghusl from janabah, menstruation, and post-childbirth bleeding until Fajr?

If a woman sees that she has become pure before Fajr, she must fast. There is no harm in delaying the ghusl until after Fajr, but it is not permissible to delay it until after sunrise. Similarly, a person in a state of janabah (major ritual impurity) is not permitted to delay ghusl until after sunrise. A man must hasten to perform ghusl to catch the Fajr prayer with the congregation.