Noninvasive DNA testing is to obtain genetic materials by drawing venous blood from pregnant women. Compared with amniocentesis, villous puncture and umbilical vein puncture, these tests are called noninvasive testing. It should be noted that non-invasive DNA testing is not a simple and universal method, but has some limitations, mainly for trisomy 21, trisomy 18 and trisomy 13. However, according to relevant research reports, chromosome aneuploidy diseases account for 80-95% of prenatal genetic diseases, especially trisomy 21 and trisomy 18, which have been the focus of birth defect prevention and control in China. Therefore, although noninvasive DNA testing can only detect three kinds of chromosomes, it is still representative.
The medical information network has learned that non-invasive DNA testing still can not diagnose whether the fetus has problems, because it is only a way of prenatal screening, not a means of prenatal diagnosis. Even if the non-invasive DNA test is not qualified, it does not mean that the fetus must have problems, but the probability of problems is relatively high, and further prenatal diagnosis such as amniocentesis and umbilical cord blood puncture is needed.
Noninvasive DNA testing is mainly suitable for people
1. The pregnant women who were older than 35 years old were not willing to choose invasive prenatal diagnosis;
2. Pregnant women with high risk of serology in the first and second trimester of pregnancy, or single index value change, are unwilling to do invasive prenatal diagnosis;
3. Pregnant women with high NT value or other abnormal anatomic structure were unwilling to choose invasive prenatal diagnosis;
4. Pregnant women who are not suitable for invasive prenatal diagnosis, such as virus carriers, placenta previa, placenta hypoplasia, oligohydramnios, negative Rh blood group, abortion history, threatened abortion or precious children, etc;
5. If amniocentesis cell culture fails, pregnant women are unwilling to accept or unable to make invasive prenatal diagnosis again;
6. The pregnant women who wish to exclude trisomy 21, trisomy 18 and trisomy 13 syndrome voluntarily choose to undergo non-invasive prenatal testing;
7. For the pregnant women with psychological disorders in prenatal diagnosis such as amniocentesis and umbilical cord blood puncture.
