Brown discharge a week before menstruation is commonly caused by endocrine disorders, contact bleeding, abnormal pregnancy, and uterine and cervical diseases.
Luteal insufficiency before menstruation causes the endometrium to lose luteal support, but the bleeding is low, which can cause brown discharge a week before menstruation.
Contact bleeding can be caused if sex is too intense or there is trauma to the vagina, etc. Ectopic pregnancy, pre-metastatic abortion, etc. may also cause bleeding, which will show up as brown discharge when the blood volume is low. Cervicitis, endometritis, cervical cancer and other diseases can also cause abnormal bleeding.
The causes of brown discharge in the week before menstruation are too many to list, and you need to go to the hospital for a clear diagnosis and then active treatment.