At 28 weeks of pregnancy, daily oxygen intake is not recommended if there is no chest tightness in pregnant women or intrauterine distress of the fetus. 1. Chest tightness of pregnant women: some pregnant women may experience chest tightness, dyspnea and other uncomfortable symptoms during pregnancy, at this time, appropriate oxygen can help to improve the oxygen content of the blood of pregnant women and the fetus, which can help pregnant women to improve the uncomfortable symptoms. 2. Fetal intrauterine distress: during pregnancy, if the fetal heart changes, fetal movement is abnormally active, amniotic fluid changes in character, it is necessary to suspect that the fetus is in intrauterine distress, at this time, appropriate oxygen inhalation can help to interrupt the process of fetal hypoxia, to improve the survival environment of the fetus. If too much oxygen is inhaled, it may cause oxygen toxicity in pregnant women, which may affect the development of the fetus. Therefore, if the pregnant woman does not have obvious chest tightness or intrauterine distress, it is not recommended to inhale oxygen every day. Pregnant women should seek prompt medical attention if they experience any physical discomfort.