Hidden pain on the left side of the abdomen in mid-pregnancy may be caused by the uterus enlarging and pulling, or it may be caused by miscarriage or gastrointestinal discomfort, gynecological diseases, etc., which need to be examined and treated. 1. The uterus is enlarged and pulled. Mid-pregnancy fetal development faster uterine enlargement, the enlarged uterus stretch uterine round ligament, which will appear abdominal pain symptoms, especially after exertion or standing for a long time is more obvious, usually after resting the symptoms will get better, can be temporarily observed, do not need treatment. 2. Pre-eclampsia. The left side of the abdomen in mid-pregnancy may also be a sign of miscarriage due to a variety of reasons, usually abdominal pain and lumbago, vaginal bleeding and other symptoms, and abdominal pain symptoms last a long time, can not be relieved on their own. Ultrasound can be done to confirm the diagnosis under the guidance of the doctor using magnesium sulfate to inhibit uterine contractions to protect the fetus treatment. 3. Gastrointestinal discomfort. Mid-pregnancy abdominal pain on the left side of the stomach may also be improper diet or cold, bacterial infection caused by gastroenteritis symptoms, often abdominal pain, loss of appetite or diarrhea and other symptoms. Can follow the doctor’s instructions to use medication. 4. Gynecological diseases. Mid-pregnancy, the left side of the abdomen hidden pain should also check whether it is pelvic inflammatory disease or adnexitis and other gynecological diseases, there will be increased leukorrhea, odor and abdominal pain, lumbar pain and other symptoms, can be combined with ultrasound and gynecological examination to confirm the diagnosis, under the guidance of the doctor to give amoxicillin or cefixime dispersible tablets and other medications for symptomatic treatment. If the symptoms continue to be unrelieved, it is recommended to consult a doctor in time to avoid delaying the condition.