Fetal heart rate monitor for home use every day is basically no effect on the fetus, but can not rely solely on hearing the fetal heart to judge the safety of the fetus in the womb. Fetal heart monitor for home use is generally not too much radiation, so when used every day on the fetus is basically no effect. However, pregnant women can not rely solely on the ability to hear the fetal heart, can judge the fetus in the uterus is safe, because the fetal heart will disappear 24 hours after the disappearance of fetal movement, so it is still necessary to count the fetal movement to accurately assess the situation of the fetus in the uterus. Fetal movement counts are performed after 28 weeks of gestation and are normal for ≥10 movements/2 hours. When fetal movement <10 times/2 hours or 50% reduction suggests the possibility of fetal hypoxia, we should go to the hospital in a timely manner, and ultrasonography, umbilical blood flow monitoring and fetal heart rate monitoring to assist in the diagnosis of a clear diagnosis or a high degree of suspicion of the need for timely termination of pregnancy, in order to ensure the safety of mothers and infants.