Maternal peripheral blood can be used to detect genetic diseases, but it has certain limitations, and timely obstetric examination should be done during pregnancy. During pregnancy, the fetus ingests nutrients needed for growth from the mother through the placenta, and at the same time, the free DNA fragments of the fetus can also enter the mother’s peripheral blood, and the extraction of the mother’s peripheral blood can obtain the DNA fragments of the fetus, and by analyzing the DNA of the fetus, it can be detected whether the fetus suffers from chromosomal genetic diseases, which is clinically referred to as a non-invasive DNA test. It should be noted that this non-invasive DNA test has certain limitations, it can only clarify the three major types of chromosomal disorders commonly found in fetuses: trisomy 21, trisomy 18, and trisomy 13, and the accuracy of the test is not 100%, and there is a certain degree of diagnostic error. Pregnant women should under the guidance of professional physicians to do a good job of obstetric examination during pregnancy, so as not to delay the condition, resulting in adverse pregnancy outcomes.