The common causes of brown discharge during sex and falling abdomen are cervical lesions, endometritis, etc. It may also be due to physiological reasons, and it is recommended to consult a doctor in time to find out the cause of the disease, and common treatments include medication, surgery, and so on. 1. Physiological reasons: if a woman is in the ovulation period, abdominal pain, coffee-colored discharge is ovulation bleeding, is a normal phenomenon. There is no need for special treatment, and it will return to normal after the ovulation period. 2. Cervical lesions: when patients suffer from cervicitis, cervical polyps, precancerous lesions of the cervix and cervical cancer, the tissues will become brittle, and contact bleeding will occur after intercourse. For cervicitis, patients can take levofloxacin, ornidazole and other medicines as prescribed by doctors for treatment; for cervical polyps, precancerous cervical lesions and cervical cancer patients, surgical treatment can be taken. 3. Endometritis: Endometritis may cause fever and lower abdominal pain, and there may be increased secretions, and may be accompanied by pain during sexual intercourse and bleeding. It can be treated with antibiotics, such as metronidazole and tinidazole, as prescribed by the doctor. If there is a brown discharge during sex with a falling abdomen, it is recommended to consult a doctor in time to avoid delaying the condition.