Physiologic hyperactivity of the fetus is normal. If there is sudden hyperactivity of the fetus, it is considered abnormal. 1. Normal physiological phenomenon (1) Strictly speaking, fetal movement will appear from about 7 to 8 weeks of pregnancy, but early fetal movement is usually not obvious, and pregnant women are not easy to feel, to the middle of the pregnancy is about 13 to 15 weeks, the beginning of obvious fetal movement, which can be felt by pregnant women. To reach about 28 weeks of pregnancy, the fetus has basically developed completely, then the fetal movement will gradually increase, up to the active period of fetal movement, to reach 38 weeks later, fetal movement will gradually decrease. (2) Fetal movement is also affected by a variety of factors, such as when pregnant women eat too much, or when the mood of excitement, the fetal movement will change, the fetal movement increased. 2. Abnormal phenomenon (1) If the umbilical cord is tightly wound around the neck when the fetus is moving, it will cause the fetus to lack oxygen in the uterus, and there will be a sudden increase in abnormal fetal movement, such as strong and continuous fetal movement. (2) Abnormal function of the placenta or external stimulation can also lead to fetal hypoxia, resulting in a sudden increase in fetal movement. Whether it is a normal physiological phenomenon or caused by disease, pregnant women are generally unable to accurately determine, so when you feel abnormal fetal movement, you should consult a doctor as soon as possible, do not delay the condition.