Fetal neck u-shaped depression means the presence of fetal umbilical cord entanglement. Umbilical cord entanglement may be due to the fact that in the middle of pregnancy, the intrauterine space is larger and the fetus is smaller, so the range and amplitude of movement within the space is relatively large, resulting in fetal umbilical cord entanglement, which has a certain chance of wrapping around the neck, and there may also be wrapping around the torso or wrapping around the limbs, which is a more frequent phenomenon. Umbilical cord entanglement does not cause serious maternal complications and can still be delivered naturally. However, in rare cases, the umbilical cord is too short or too tight, and the number of weeks of umbilical cord entanglement is too large, which may cause localized ischemia of the umbilical cord, and in severe cases, may lead to ischemia and hypoxia of the fetus, or even fetal demise in the uterus. Pregnant women are advised to count the fetal movements and strengthen monitoring and observation. Follow the doctor’s instructions and go to the hospital for regular checkups to understand the development of the fetus. Maintain a good mood and avoid prolonged tension, depression and irritability.