It may be a normal physiological phenomenon, but it may also be caused by endocrine disorders, cervical adhesions, uterine cavity adhesions and other reasons. 1. Normal physiological phenomenon: when menstruation first comes, the endometrium sheds a small amount, which can cause a little bit of menstruation, and then the amount gradually increases. 2. Endocrine disorders: due to mental stress, overwork, excessive weight loss and other reasons can lead to luteinizing hormone, gonadotropin and other hormone level disorders, menstruation is too small, menstruation only a little. 3. Cervical adhesion: due to cervical inflammation, mechanical damage to the cervix (such as after cervical conization, abortion, curettage, etc.), the cervix is incompletely adhered to the cervix, and the menstrual blood is not discharged smoothly when menstruation occurs, which results in only a little bleeding when menstruation occurs, and the bleeding is not able to come out. 4. Uterine cavity adhesion: repeated scraping, especially scraping accompanied by infection, endometrial resection after infection and other reasons lead to the uterine cavity adhesion, the uterine cavity endometrium area is reduced, caused by menstruation just a little bit of not come out. There may be other reasons why menstruation does not come out just a little bit, so please consult your doctor in time and find out the reasons and give appropriate treatment under the doctor’s guidance.