It is usually normal for the fetus to move at night but not during the day. The fetal movement varies from one fetus to another and from one pregnant woman to another in terms of physical condition and activity level. First of all, there is a sleep cycle of the fetus in the uterus, usually early morning, afternoon and night are relatively active fetal movement, during this period the fetal sympathetic nerve is relatively excited, will be active, the daytime fetal movement is relatively less. The normal fetal movement is not less than 3-5 times per hour, as long as the fetal movement has its own regularity and does not vary much, it is a normal situation. Secondly, pregnant women are disturbed by more factors during the day, may not notice the fetal movement, and at night when the environment is quiet, the senses become sharper, more sensitive to fetal movement. And after dinner, activity is reduced, more nutrition and oxygen can be absorbed by the fetus, so that the fetal activity becomes larger. Finally, if the pregnant woman sleeps in a position that presses the fetus, it may also lead to intense fetal movement, which usually occurs in the flat position and may be relieved by switching to the left side. It is important to note that normal fetal movement is usually continuous and regular, if the fetus usually moves normally and suddenly appears to move at night but does not respond during the day, it may indicate fetal hypoxia, usually accompanied by an increase or decrease in the number of fetal movements, it is recommended to consult a doctor in a timely manner, ultrasound examination or fetal heart monitoring can be given to clarify the cause and then timely treatment.