1. If her habit is more than 4 days, it is not permissible to have intercourse on the fourth day of her cycle even if her bleeding has ceased. When she stops bleeding on the fourth day, she should take a bath and start performing her Salaat, etc. even though intercourse is not permitted.
2. Intercourse will only be permitted once she passes the normal number of her period days.
3. Assuming she bleeds for 4 days only in the next cycle as well, we will now say that she has developed a new habit, i.e. 4 days. So now, she may have intercourse after 4 days, but not in the first instance.
and Allah Ta’ala Knows Best
Mufti Muhammad Kadwa
FATWA DEPT.