Non-invasive DNA, or non-invasive chromosome testing, screens fetuses for chromosomal abnormalities based on the results of the test. Non-invasive chromosome testing is used to detect the probability of a fetus suffering from congenital hereditary diseases by extracting fetal DNA from the peripheral blood of the pregnant woman, especially for chromosomal disorders such as trisomy 13, trisomy 18, trisomy 21, and sex chromosome aneuploidy, which have a relatively high detection rate. The accuracy and comprehensiveness of non-invasive chromosome testing is higher than that of Down’s screening, and it is recommended that women with abnormalities in Down’s screening or who are older than 35 years of age should choose non-invasive chromosome testing if they are eligible. If there is an abnormality in the non-invasive test, amniocentesis will be performed to clarify the diagnosis if necessary.