Occasionally a little pain in the left abdomen and a small amount of light blood during sex may be due to ovulation bleeding, endometriosis, chronic pelvic inflammatory disease, cervical lesions and other reasons. 1. Ovulation bleeding: if you have sex just in time for ovulation, and after ovulation due to a transient drop in hormone levels in the body, it may lead to a small amount of endometrial shedding, causing slight pain in the abdomen and bleeding symptoms. 2. Endometriosis: after suffering from endometriosis, there may be a little pain in the stomach after sex, and may also be accompanied by a small amount of vaginal bleeding. 3. Chronic pelvic inflammatory disease: because the pelvis is in long-term congestion, tissue adhesions, edema, etc., and stimulation after sex, may aggravate the edema, congestion symptoms, so the lower abdomen pain symptoms. And due to inflammatory stimulation, the endometrium is relatively fragile, there may also be a small amount of bleeding. 4. Cervical lesions: for those who suffer from cervicitis, pre-cancerous cervical lesions, cervical cancer and other cervical diseases, there may also be a small amount of blood during sex, due to the stimulation of the lesions, there may also be accumulated ligaments, so there will also be occasional stomach pain symptoms. The causes of occasional left abdominal pain, sexual intercourse with a small amount of light blood are more reasons, it is recommended to go to the hospital in a timely manner, clear cause of the cause of the disease, follow the doctor’s instructions, the cause of the treatment.