Both amniocentesis and amniocentesis are methods of prenatal screening, but amniocentesis can be used for prenatal diagnosis of fetal genetic disorders and is more accurate than non-invasive testing. For pregnant women who are at higher risk for trisomy 21 disorders, doctors may recommend amniocentesis for fetal DNA testing for prenatal diagnosis. First, noninvasive testing is easier and safer, but less accurate than amniocentesis. For routine prenatal screening and between 12-22+6 weeks of gestation, screening fetal DNA for risk of trisomy 21, 18, and 13 using peripheral blood drawn from the mother is a simpler and more accurate method. However, noninvasive tests are only used as prenatal screening and cannot be used as a basis for diagnosis because they can affect the accuracy of noninvasive tests for twin pregnancies, placental chimerism, and maternal tumors, and cannot make the accuracy of noninvasive tests 100%. Secondly, for pregnant women with positive non-invasive tests for genetic disorders, amniocentesis is still required to confirm the diagnosis. Amniocentesis is an ultrasound-guided puncture of the amniotic cavity in which amniotic fluid is extracted to obtain fetal cells or DNA and to examine it genetically. It is usually indicated for pregnant women after 16 weeks of pregnancy, but there may be a risk of intrauterine infection or blood contact between mother and baby, or miscarriage. Therefore, the doctor will choose the appropriate test according to the age, gestational week, physical condition and genetic risk of the pregnant woman, and it is recommended to follow medical advice.