The appropriate concentration of oxygen inhalation for pregnant women is between 27%-29%, that is, the oxygen flow rate is between 1.5-2.0L/min. Oxygen inhalation for pregnant women is suitable for the middle and late stages of pregnancy. When pregnant women or fetus have obvious hypoxia symptoms in the early stage of pregnancy, oxygen inhalation can obviously increase the oxygen saturation in the blood of pregnant women, and improve the symptoms of chest tightness, palpitation, shortness of breath, and poor sleep, etc., which are caused by hypoxia in pregnant women. It can rapidly increase the blood oxygen content in the blood of the placenta and umbilical cord, and improve the abnormal fetal heart rate and abnormal fetal movement caused by hypoxia. However, the concentration of oxygen is not the higher the better, pregnant women inhaling too high a concentration of oxygen is likely to lead to fetal retinal damage, but also easy to cause changes in the internal environment of pregnant women. When giving oxygen to pregnant women, they must strictly follow the medical advice of the attending physician and choose the appropriate oxygen concentration and flow rate.