An abdominal ultrasound is not always enough to determine the cause of old early menstruation, because diseases of the reproductive system are not the only causes of early menstruation. Common causes of early menstruation include luteal insufficiency, unscientific lifestyle and organic diseases. 1. Luteal insufficiency: It is often manifested as early menstruation, but there are many causes of luteal insufficiency, such as insufficient secretion of related hormones, hyperprolactinemia and so on. These need to be diagnosed through blood tests and cannot be clarified through abdominal ultrasound. 2. Unscientific lifestyle: including excessive mental stress, irregular work and rest, etc., may also lead to endocrine disorders and manifested as early menstruation, which can not be clarified by abdominal ultrasound. 3. Organic diseases: such as inflammation or tumor of the reproductive system, adenomyosis, pituitary gland and hypothalamus diseases, some of them can be clarified by abdominal ultrasound examination. In addition, there are many other causes of early menstruation, it is recommended to go to the gynecology department of the hospital in a timely manner to identify the causes and then treated under the guidance of the doctor.