Can a woman who is experiencing [post-natal bleeding or any non-menstrual uterine bleeding] fast?

During the period in which a woman with irregular bleeding (mustahadah) determines that the blood descending is menstrual blood, she is considered menstruating (ha’id) and the rulings for a menstruating woman apply to her. When her menstruation ends, she performs ghusl (ritual bath), fasts, prays, and her husband may approach her, even if the bleeding continues. This is because the blood after menstruation is considered istihadah (irregular bleeding), which is blood from a vein and not menstrual blood. It does not prohibit what menstrual blood prohibits, and prayer and fasting are obligatory during this time.