Istihada إستحاضة is defined as the abnormal vaginal bleeding which is not the regular  menstrual bleeding. Blood of Istihada is usually yellowish and cold and is emitted without gush or irritation and it also not thick. Menstruation bleeding has minimal period which is three days and maximum days which are ten days, while Istihada has no minimum nor maximum days. During menstruation, female does not pray Salah nor fasts, but during Istihada, she has to perform Salah and fast during the month of Ramadan. She needs just to perform Wudu for every Salah if the bleeding is less than filling the pad. If the bleeding fills the pad,b she has to add one Ghusl before morning Salah. If the bleeding is more than that and it fills the pad and leaks out of the pad, then she had to perform three Ghusls; one before morning Salah, second before Zohr Salah and the third a Ghusl before Maghrib Salah.

Wassalam.