If brown discharge persists even after menstruation, the first common cause is uterus-related diseases, such as benign uterine diseases, including cervical polyps, cervical fibroids, submucosal fibroids, endometrial polyps, bulky interstitial fibroids, and adenomyosis, all of which may result in brown discharge. In addition, there are some malignant tumors of the uterus that may also occur, such as cervical cancer, endometrial cancer, and uterine sarcoma. Once again, there may be some endocrine disorders that cause a continuous brown discharge after menstruation.