Non-invasive, also known as non-invasive DNA, Down’s screening shows a low risk but human chorionic gonadotropin HCG is a little on the high side. Pregnant women who are in a position to do so can further undergo non-invasive DNA testing to further screen the probability of the fetus having a congenital disease. A Down’s syndrome test result with a risk value in the low-risk range indicates that the probability of the fetus having a congenital hereditary disease is relatively low. Down screening shows low risk but a little on the high side of HCG, HCG is in the high level range throughout the pregnancy and the HCG range varies from week to week, as long as it is within a reasonable range it is normal. Down screening shows low risk but HCG is a little high, can not determine whether the fetus is abnormal, the condition of the pregnant woman can be further non-invasive DNA, further screening of the probability of the fetus with congenital diseases. The result of non-invasive DNA test is also low risk, pregnant women can also be more assured that the fetus is not likely to develop chromosomal abnormalities.