The duration of oxygen intake for pregnant women is about 20 minutes, and the duration of each oxygen intake should not be too long, it is better to absorb oxygen once in two days, after a week, and then again in 1-2 weeks, oxygen intake can increase the blood supply of the placenta. Oxygen intake for pregnant women is best carried out in a hospital, the oxygen should be pure oxygen used in the hospital and the concentration should not be too high, oxygen intake should be carried out under the guidance of a doctor, not just any oxygen intake to prevent bad effects on the fetus in the womb. The usual reason for oxygen intake in pregnant women is the lack of oxygen in the fetus in the uterus, how to determine the lack of oxygen in the fetus becomes the key. First of all, if there is a sudden decrease in fetal movement, it may mean that the fetus is hypoxic. If the fetal movement is suddenly accelerated, it also means that the fetus is hypoxic, which may be due to external forces and other effects, and may cause premature birth, so oxygen is needed. During pregnancy, it is recommended that pregnant women have regular maternity checkups and communicate more with their doctors to determine whether the fetus needs oxygen.