The absence of fetal heartbeat may be caused by the relatively short duration of pregnancy, late implantation of the fertilized egg, or fetal eclampsia. 1. Short pregnancy time: some women are pregnant for a relatively short period of time, for example, the pregnancy sac can be seen through ultrasound examination on the 35th day, this time there is no fetal heart development is normal, until 42 days of pregnancy will appear fetal heart. 2. Late implantation of the fertilized egg: some women usually have a long menstrual cycle, ovulation time is late, the implantation of the fertilized egg is relatively late, 50-60 days may not be able to see the fetal heart, dynamic review ultrasound can only be seen after the fetal heart. 3. Fetal Arrest: The absence of fetal heart may be a nulliparous pregnancy, or it may be that the fetal heart has already appeared, but the fetal heart stops pulsing during the development process, both of which are fetal arrest. Fetal arrest may be caused by chromosomal abnormalities in the embryo, endocrine disorders, maternal viral infections, and long-term exposure to radiation. After pregnancy, it is determined that the fetus without fetal heart will not be able to continue the pregnancy normally, and should go to the hospital in time to deal with it.