Fetal hypoxia can be dangerous for several days and is related to a combination of factors such as the nature of hypoxia, the degree of hypoxia, and the fetal tolerance to hypoxia. Fetal intrauterine hypoxia refers to the lack of oxygen supply to the fetus caused by various reasons and is commonly seen in mothers with aging placenta, significantly reduced amniotic fluid volume or umbilical cord abnormalities and fetal growth restriction. This disease is an obstetric emergency because the fetus is the first to damage the function of brain cells when hypoxia occurs, usually mild hypoxia has little effect on the fetus if it is treated promptly, but if the hypoxia lasts too long or the fetus tolerates hypoxia poorly, it may endanger the life of the fetus. Acute intrauterine hypoxia is usually dangerous in about 24 hours, while chronic intrauterine hypoxia may not result in intrauterine stillbirth even for a long time, but it may affect the fetal intelligence and physical development. It is recommended that mothers should closely observe the changes of fetal heartbeat and fetal movement during pregnancy, have regular maternity checkups, strengthen fetal heartbeat monitoring when abnormalities are detected, and have the obstetrician intervene as soon as possible.