A Down’s screening result of critical risk for trisomy 21-trisomy should be further examined by non-invasive DNA or amniocentesis to rule out fetal chromosomal abnormalities.
Down’s screening is a measure of prenatal screening, not prenatal diagnosis, there are generally three results, respectively, low risk, critical risk and high risk, of which the critical risk and high risk suggests that the probability of fetal chromosomal abnormality is higher, such as NT test <2.5 in early pregnancy, you can check the non-invasive DNA, which has a low rate of false positives and has a high detection rate of 21-trisomy syndrome.
Amniocentesis is recommended for Down’s syndrome with a critical risk of trisomy 21-trisomy along with an NT result ≥2.5. Amniocentesis is a prenatal diagnosis, it is the gold standard for determining fetal chromosomal abnormalities, this is an invasive test, it may lead to complications such as miscarriage, bleeding, but the incidence is low, if the pregnant woman has signs of miscarriage, infection, etc. should avoid the test.
The above tests should be done in a regular hospital to avoid errors, and regular obstetric checkups can be done after the tests have no problems. During pregnancy, you should eat a reasonable diet, quit smoking and drinking, and avoid anxiety.