The best time for oxygen in pregnancy should be as follows: first, the best time for oxygen in pregnancy is different for different ages, the best time for oxygen in pregnancy for women aged 20-25 is in 10-15 weeks, the best time for oxygen in pregnancy for women aged 25-30 is in 15-18 weeks, the best time for oxygen in pregnancy for women aged 30-35 should be in 25-30 weeks, pregnant women aged more than 35 years old The time of oxygen intake is more difficult to determine, because they are older and relatively weaker, so the specific situation should be analyzed. Secondly, the best time for oxygen intake should also be determined with the mother’s physical condition. If the mother’s physical condition is good and the fetus is developing well in the womb, the time for oxygen intake may be around 15-20 weeks, because at this time the fetal nervous system and cardiopulmonary development is a critical period, and the oxygen consumption and the demand for nutrition are relatively large, so oxygen intake should be carried out at this moment. Thirdly, the best time for oxygen intake is also related to a person’s genetics, that is to say, if the person is born with a better constitution, he may not necessarily need it. If you are born with a weaker constitution, you may need it earlier and for a longer period of time.