The following causes of intrauterine bleeding are common: 1. submucosal fibroids, which grow into the uterine cavity and can lead to poor contraction of the uterus, which can cause bleeding. 2. bleeding due to endometrial polyps or inflammation of the endometrium. 3. endocrine disorders, such as estrogen deficiency or progesterone deficiency, can clinically lead to bleeding. 4. 4. Cancer of the endometrium can lead to intrauterine bleeding and is often accompanied by a foul odor. 5. If there is coagulation dysfunction and thrombocytopenia, both may lead to intrauterine bleeding. Therefore, when vaginal bleeding occurs in addition to menstruation, it is important to find out what causes it, and only when the cause is found can the correct treatment be given.