There are more reasons for brown discharge after menstruation, which may be cervical lesions, endometrial lesions, vaginal lesions, birth control ring stimulation, and so on. 1. Cervical lesions: cervical inflammation, cervical polyps, cervical tuberculosis, cervical cancer, etc., may lead to brown discharge after menstruation. 2. Endometrial lesions: endometrial inflammation, endometrial polyps, endometrial hyperplasia, adenomyosis, endometrial cancer, etc., may lead to brown discharge after menstruation. 3. Vaginal lesions: Trichomonas vaginitis, vulvovaginal pseudomycosis, bacterial vaginosis, atrophic vaginitis, etc., may lead to vaginal congestion and edema and cause a small amount of bleeding to form brown discharge. 4. Stimulation of the birth control ring: just three months after the implantation of the IUD, or the displacement of the IUD, etc., may lead to the stimulation of the endometrium by the birth control ring, causing irregular endometrial shedding and bleeding phenomenon. There may be other reasons for the brown discharge after menstruation, so you need to go to the hospital in time to get a clear diagnosis, and then under the guidance of the doctor to actively treat the diagnosis.