Pregnant women in the fourth month of pregnancy, the left side of the stomach pain is relatively common, may belong to the normal physiological pain, may also belong to the pathology of the pain, such as preeclampsia, gastrointestinal dysfunction, etc., need to be clear cause of the symptomatic treatment. A common cause 1, physiological pain: with the continuous growth and development of the fetus in the uterus, the uterine muscle ligaments to withstand more and more tension, coupled with the enlarged uterus continues to oppress the surrounding tissues and organs, all of these factors will lead to pregnant women feel the left side of the stomach ache; 2, pathologic pain: when pregnant women appear to have pain in the lower abdomen accompanied by vaginal bleeding, we should pay attention to whether there is a preeclampsia possibility of miscarriage. Some pregnant women due to improper diet during pregnancy caused by gastrointestinal dysfunction, can also lead to diarrhea, abdominal pain. Some pregnant women have had surgery on the abdomen, resulting in wounds and intestinal adhesions leading to intestinal obstruction, which can also cause abdominal pain on the left side of the pregnant woman. Second, the treatment 1, when the pregnant woman appeared left abdominal pain, if only mild or in the attack can be relieved by resting for a while, and there is no bleeding symptoms, can be temporarily observed, do not need special treatment; 2, if the pain continues to intensify and accompanied by vaginal bleeding symptoms, to immediately go to the hospital to check whether there is the possibility of preterm miscarriage, for the specific circumstances of the treatment of fetal preservation. For non-obstetrics and gynecology diseases, the need for professional doctors combined with the specific circumstances of pregnancy for symptomatic treatment. Third, precautions pregnant women do not panic when the left side of the abdominal pain, pay more attention to rest, a balanced diet, do not eat cold food, moderate exercise, do not engage in heavy labor, do not stay up all night, keep a happy mood, safe through pregnancy.