Menstruation three days in advance, menstrual bleeding, seven days is not clean, may be caused by pregnancy or endocrine disorders. 1. Pregnancy: If a woman has had sex before, it may be caused by pregnancy. At this time, the vaginal bleeding is not menstruation, but vaginal bleeding caused by biochemical pregnancy, preeclampsia or ectopic pregnancy, and you can go to the regular hospital to receive the blood HCG test, i.e., human chorionic gonadotropin and progesterone test, to make it clear whether you are pregnant or not. 2. Endocrine disorders: this condition can also lead to hormone secretion disorders in the female organism, which in turn leads to menstrual disorders, and can be diagnosed clearly by drawing sex hormone six, thyroid function, and so on. In addition, patients with irregular vaginal bleeding may also see endometrial polyps, cervical polyps, endometritis and other diseases. It is recommended that women with this condition should consult a doctor promptly to make a clear diagnosis and, depending on the results, be treated under the guidance of a specialist.