Can You Delay Ghusl?
Question

Is it permissible to delay ghusl for janabah until after dawn has broken? Is it permissible for women to delay ghusl following the end of menstruation or post-natal bleeding until after dawn has broken?
Praise be to Allah.If a woman sees that she has become pure before Fajr, then she has to fast, and it does not matter if she delays ghusl until after dawn has broken. But she should not delay it until the sun rises. 
The same applies in the case of janabah (impurity after sexual activity), one should not delay ghusl until after the sun has risen and in the case of men, they should hasten to do ghusl so that they can pray Fajr with the congregation in the mosque.
And Allah knows best.