Pregnant women usually take oxygen for no more than half an hour at most. This is because if the oxygen intake time is too long or the amount is too large, it will have certain effects on the fetus. When the fetus moves abnormally during pregnancy, it is necessary to consult a doctor in time for a fetal heartbeat monitoring examination to determine whether intrauterine hypoxia has occurred in the fetus. If there is intrauterine hypoxia, pregnant women usually need to take oxygen in time. However, it should be noted that pregnant women who inhale oxygen generally not more than half an hour at most, can not one-time inhalation of too much oxygen, because too much oxygen inhalation time is too long, there will be a certain impact on the growth and development of the fetus, such as retinal damage, and may even lead to fetal blindness. Therefore, pregnant women in the oxygen, under the guidance of the doctor to carry out, must be appropriate to control the oxygen inhalation time, each time the oxygen inhalation time is about half an hour can be.