Pregnant women are four months pregnant, today suddenly the right side of the stomach pain, may be physiological factors, such as increased uterine compression of abdominal organs; may also be pathologic factors, such as preeclampsia, abdominal organs inflammation, etc., need to be diagnosed according to the signs of pregnant women and related examination and then dealt with. First, physiological pain: pregnancy: pregnant women in the fourth month of pregnancy, the uterus began to gradually become larger, the right side of the uterine ligaments pulling, taut, can trigger the pulling pain, while the right side of the uterus of the annexes, intestinal tubes have a certain squeeze, may lead to the right side of the tummy pain. Physiological pain is generally tolerable, can be relieved with the change of position, not accompanied by other abnormal symptoms, such as fever, nausea, etc., generally do not need special treatment. Second, pathologic pain 1, miscarriage: If the pregnant woman has persistent pain aggravated by vaginal bleeding, should be alert to the possibility of miscarriage, it is recommended to go to the hospital to do ultrasound, to see whether there is the possibility of miscarriage. If it is preeclampsia, the pregnant woman needs to be treated with birth control; 2, gynecological inflammation: if it is the right side of the adnexitis, salpingitis, etc., or inflammation of abdominal organs, such as appendicitis, enteritis, intestinal spasm, intestinal obstruction, etc., can cause pregnant women with sudden pain in the right side of the abdomen. This pain is generally heavier, change position can not be relieved, need to go to the hospital in a timely manner, identify the cause of the disease, line targeted treatment; 3, acute abdomen: if appendicitis, pelvic inflammatory disease, acute intestinal obstruction, etc., there will be the right side of the stomach pain, and pregnancy has nothing to do with the pain caused by abdominal diseases, identify the cause of the disease, you can perform conservative treatment or surgical treatment.