A bouncing belly at 30 weeks of pregnancy is usually a fetal movement felt by the pregnant woman as the baby moves around in the uterine cavity. In the 30th week of pregnancy the uterine cavity is not as spacious as in early pregnancy, so the fetal movement is more obvious and easily perceived, and may be one jump after another. The first thing to determine is whether it is a regular beating, if it is a regular beating, it is generally normal. If there is a decrease in fetal movement, it is an abnormal situation and requires timely consultation to assess whether the fetus is safe. I. Normal: 1. regular fetal movement: there is a circadian rhythm of the fetus in the uterine cavity, and regular fetal movement will occur at the corresponding fixed period of time every day; 2. fetal hiccups: the fetus in the process of swallowing amniotic fluid, sometimes drinking too fast, the septum muscle is stimulated, resulting in hiccups appearing a jumping movement; 3. abdominal aortic pulsation: after pregnancy, the uterus increases, the abdominal aorta is compressed beating significantly, the frequency is the same as the heartbeat frequency the same. Second, abnormal: if the fetus intrauterine hypoxia, can appear frequent fetal movement, need to go to the hospital as soon as possible to do fetal heart monitoring, if the umbilical cord around the neck or other more serious cases, usually need to take measures as soon as possible to deliver, to avoid intrauterine asphyxia and other more serious cases of fetal asphyxia.