The causes of brown discharge in women before menstruation are as follows: First, due to the presence of luteal insufficiency, early atrophy of the corpus luteum will cause the endometrium to peel off earlier and there will be brown discharge. The brown discharge may also be due to female exertion or cold stimulation. Three, may be related to women with cervical erosion, cervical polyps and other chronic inflammatory diseases. Fourth, when suffering from uterine fibroids, adenomyosis and other gynecological may also lead to endocrine disorders, the early arrival of menstruation. Under normal circumstances, it is normal for women to have their menstruation a week early or a week late. If women have their menstruation a week or more early, it is best to go to the hospital for gynecological ultrasound and sex hormone examination to clarify the cause and corresponding treatment.