After 20 weeks of pregnancy, the baby dies in the womb, called stillbirth. There are obvious signs of stillbirth, first of all, the pregnant mother will be conscious of the disappearance of fetal movement, and the belly stops continuing to grow with time, and when the doctor carries out a labor and delivery examination, there is no way to hear the fetal heartbeat. Ultrasound examination of the fetus can clearly diagnose stillbirth. The causes of stillbirth are divided into three main aspects: i. Factors of the placenta and umbilical cord are one of the most common causes. For example, if placental abruption occurs or the umbilical cord is twisted or knotted before the baby is delivered, it may lead to severe oxygen deprivation and stillbirth. Secondly, if the fetus has serious deformities and growth restriction, it will also be prone to stillbirth. Third, the pregnant mother has serious pregnancy complications, such as gestational hypertension and diabetes. After stillbirth occurs, if the fetus stays in the uterine cavity for too long, it may cause clotting disorders in the pregnant mother. Most fetuses will expel themselves within 2-3 weeks after death, and if the death is still not expelled for more than 4 weeks, the chances of disseminated intravascular coagulation will increase significantly, and can even cause serious bleeding.