For the vast majority of pregnant women, it is normal to feel a decrease in fetal movement at 39 weeks of pregnancy. In late pregnancy, as the fetus grows, the amount of amniotic fluid in the uterine cavity gradually decreases, the space for fetal movement will be very small, and most of the fetus is already in the pelvis and articulated in the pelvis. The fetal range of motion is more restricted, and the fetal movements are less frequent than before, and are less frequent than before, but at this time the pregnant mother still needs to be alert and count the fetal movements carefully. The fetal movements are still present in other parts of the body, such as partial movements of the limbs, head turning movements, hand and foot movements, etc., and the pregnant mother can still feel the slightest fetal movements at this time. In addition, it is very important to visit the hospital regularly for fetal heart monitoring to know the status of the fetus. At the end of pregnancy, there are very few pregnant women whose placenta function is damaged and there are problems with blood supply and oxygen supply, and there is a possibility of fetal death in the uterus, which will be manifested at the beginning by the disappearance of fetal movement and reduction of fetal movement. Therefore, in late pregnancy, fetal heart monitoring is a very important test.