There are many reasons for prolonged menstruation, including uterine lesions, ovarian lesions, endocrine disorders, blood system diseases, etc.: 1. uterine lesions: endometrial polyps, uterine fibroids, endometrial inflammation, endometrial cancer, uterine scar diverticulum, adenomyosis and other lesions can cause prolonged menstruation and incomplete menstruation; 2. ovarian lesions: polycystic ovary syndrome, luteinizing insufficiency, premature ovarian failure, hyperprolactinemia can also cause prolonged menstruation, which is related to fluctuations in hormone levels; 3. Cystic ovary syndrome, luteal insufficiency, premature ovarian failure, hyperprolactinemia can also cause prolonged menstruation, which is related to fluctuations in hormone levels; 3, endocrine disorders: women taking hormonal drugs or affected by emotions, environmental changes, etc., causing endocrine hormone disorders in the body, which can also lead to prolonged menstruation; 4, blood system diseases: platelet reduction, coagulation dysfunction and other blood system diseases may cause menstrual bleeding difficult to stop by itself, manifesting as a state of prolonged periods; 5, liver and kidney diseases: severe nephrotic syndrome, cirrhosis of the liver, sometimes can affect women’s menstruation, making periods prolonged; 6, other: intrauterine device placed in the uterine cavity, can also lead to abnormal state of the uterine cavity, affecting the endometrial exfoliation process, leading to prolonged periods.