Menstruation has not been clean, the endometrium of the vaginal ultrasound 3mm, and blood may be caused by endocrine disorders, uterine fibroids and other diseases. 1. endocrine disorders: refers to a part of the body or the whole body and other dysfunctions, such as luteal insufficiency or atrophic atrophy, there may be menstruation has not been clean, ultrasound endometrium 3mm, and the phenomenon of blood, you can use chorionic gonadotropin, medroxyprogesterone acetate, and other drugs under the guidance of the doctor for treatment. 2. Uterine fibroids: fibroids will compress the surrounding blood vessels, resulting in congestion and swelling of blood vessels, thus causing increased menstrual flow ﹑ prolonged menstrual period, menstruation unclean old a little blood, can be treated through the surgical method of myomectomy or hysterectomy. Therefore, patients with unclean menstruation and 3mm endometrium should go to the hospital as soon as possible and receive standardized treatment under the guidance of the doctor.