Non-invasive DNA testing can be performed from 12 to 24 weeks of pregnancy. Non-invasive DNA test is mainly used to collect peripheral blood of the mother, from which the fetal components are separated and then identify fetal chromosomes, which is used for early detection of whether the fetus has chromosomal abnormalities. Generally, it can be performed within 12 to 24 weeks of pregnancy, and it is usually recommended to do it around the 16th week of pregnancy. If the pregnancy is less than 12 weeks, the fetal component into the mother’s body is relatively weak, it is not easy to isolate the fetal component. If the pregnancy is greater than 24 weeks, the fetal components entering the mother’s body are more numerous and complex, and the screening is prone to false positives, further screening by amniocentesis with higher accuracy is required. Therefore, it is recommended that non-invasive DNA testing can be performed within 12 to 24 weeks of pregnancy, and any abnormalities should be dealt with promptly under the guidance of a doctor.