The occasional pain in the stomach of a pregnant woman at 33 weeks may be caused by the enlargement of the uterus, or it may be a false contraction or preterm labor phenomenon. 1. Uterine enlargement: 33 weeks of pregnancy belongs to the late stage of pregnancy, fetal development is relatively fast, pregnant women will pull the abdominal skin muscles after the stomach increases significantly, which will appear stomach pain phenomenon, is a normal physiological phenomenon. 2. False contractions: False contractions of varying degrees will occur in late pregnancy, contractions will cause stomach pain or abdominal hardness, tightness and other phenomena. They usually last for a short time and disappear after rest, which is also a normal physiological phenomenon. In addition, when the amplitude of fetal movement is large, it may also stimulate the stomach to occasional pain. 3. Preterm labor phenomenon: 33 weeks pregnant with occasional pain in the stomach, if the pain is obvious or lasts a long time, there is a certain regularity, may be the manifestation of preterm labor, need to go to the hospital in a timely manner to do ultrasound examination, give magnesium sulfate to inhibit contractions to protect the fetus, etc., to rest in bed and observe. In addition, 33 weeks pregnant stomach pain occasionally also be alert to whether it is gastrointestinal discomfort or increasing uterus top pressure lower edge of the ribs, etc., to determine the cause of stomach pain after symptomatic treatment.