When umbilical cord entanglement occurs in a fetus, it is mainly due to factors such as the umbilical cord being too long and fetal movement. When the umbilical cord is too long, it is easy to be entangled in the uterus, and if the fetal head is in the vicinity it will lead to umbilical cord bypass. On the other hand, when the fetus is constantly moving in the amniotic fluid, the position of the fetal head and the umbilical cord will change, making it easier for the umbilical cord to become wrapped around the neck. When the umbilical cord is wrapped around the neck pregnant women need to remain vigilant and monitor the fetal heartbeat and fetal movement to ensure the health of the fetus. If there is too little or too much fetal movement after the umbilical cord is wrapped around the neck, or if there is an abnormality in fetal heartbeat monitoring, it means that the fetus is lacking oxygen in the uterus, and then you should consult a doctor in time, and take the appropriate methods to intervene under the guidance of the doctor.