Whether a pregnant woman should do Down screening or non-invasive should be analyzed according to the specific situation. 1. Down’s syndrome: Down’s syndrome refers to the screening of Down’s syndrome. Pregnant women who are within 35 years of age and have not previously given birth to a fetus with chromosomal abnormalities can opt for Down’s syndrome screening, which is simpler and less expensive. 2. Non-invasive: non-invasive refers to non-invasive DNA test, if the pregnant woman’s age is over 35 years old, considering the higher chance of chromosomal abnormality, or has given birth to a fetus with chromosomal abnormality in the past, it is recommended to undergo the non-invasive DNA test, the cost of this test is higher than that of Down’s syndrome, but the results of the test are more accurate than that of Down’s syndrome. Each pregnant woman’s physical condition is different, and the method of examination will be different, so it is recommended to choose the appropriate examination method under the guidance of the doctor.