At 20 weeks of pregnancy, if there is no heartbeat in the fetal examination, consider the possibility of fetal arrest. There are many reasons why the fetus may stop growing at 20 weeks, such as umbilical cord factor, placental factor, or maternal illness. Umbilical cord factor means that if the umbilical cord is twisted and knotted, it will affect the blood supply and nourishment of the fetus, resulting in fetal growth failure. Placental factors mainly refer to the premature aging of the placenta or premature abruption of the placenta, which can also directly affect the nutritional supply of the fetus and cause it to stop developing. Maternal illnesses, such as viral infections, high blood pressure, diabetes, etc., which cause the body to be unable to secrete enough progesterone to maintain fetal development, may also cause mid-pregnancy embryonic arrest. If there is no heartbeat in the fetus at 20 weeks, it is important to review the ultrasound in time to make sure, so that it can be detected as early as possible and intervene as early as possible.