Non-invasive DNA testing is mainly used to check for fetal aneuploidy disorders of chromosomes 21, 18, and 13. Chromosome 22 has nothing to do with these three types of disorders, so there is no program to check for chromosome 22 in the screening program. The non-invasive DNA test is designed to screen for chromosomes 13, 18, and 21, which have a relatively high rate of trisomy. Because these chromosomal abnormalities may be the cause of fetal Down syndrome, Edward’s syndrome and so on. Other chromosomal abnormalities, which are less likely to occur clinically, are not covered by non-invasive DNA testing. So normally, non-invasive DNA testing has some limitations. If pregnant women are particularly worried about their other chromosomal abnormalities, they can choose to undergo amniocentesis to rule out chromosomal abnormalities, which is more comprehensive. Every pregnant woman should pay attention to do a good job of prenatal checkups during pregnancy, and actively listen to the advice of professional doctors to do a good job of comprehensive care and health care, which can effectively ensure the safety of the birth.