In general, slight fetal movement will occur at 18 weeks of pregnancy, but each pregnant woman is different and may not be able to notice any obvious fetal movement. As the fetus grows and develops, the pregnant woman may gradually feel the fetal movement in 18-20 weeks. At the beginning, fetal movement is relatively gentle, like a butterfly flapping its wings. As the pregnancy increases, fetal movement will gradually become more obvious and have a certain degree of regularity. After the appearance of fetal movement, pregnant women can judge the growth and development of the fetus by counting the number of fetal movements. That is, in the morning, midday and evening three hours each counting 1 hour, continuous fetal movement counted as 1 time, 3 hours cumulative number of fetal movement multiplied by 4 for 12 hours fetal movement number. Generally, the number of fetal movements per hour is 3-5 times, and the 12-hour fetal movement fluctuates about 30-40 times. In addition, pregnant women’s tension, overwork, activities, etc. may cause changes in fetal movement. Pregnant women can observe the same period of time to determine the pattern of fetal movement. If the pregnant woman does not feel obvious fetal movement, it may be caused by the pregnant woman’s abdominal fat is too thick, or the first-time mothers do not feel the fetal movement clearly, or the abnormal development of the fetus, etc., and need to further improve the ultrasound examination to clarify the development of the fetus, in order to ensure the normal growth and development of the fetus.