Sihai network

What is the purpose of Down's screening? The accuracy of Down's screening

Sihaiwang: there are many means of pregnancy test. Regular pregnancy test is the main means to ensure the safety of mother and child and to detect fetal abnormalities. One of them is Tang screen. Tang screen is to screen Tang's children. What's the purpose of Tang screen?

What is the purpose of Down's screening?

When the expectant mother is pregnant for 15-20 weeks, she can do down's screening, that is, the first time for birth inspection. Why should she do down's screening?

Down's screening refers to the screening method with special significance. It is aimed at the specific population without any corresponding disease tips (such as all pregnant women), through the screening, the high-risk population who is more likely to suffer from a certain disease is screened out for subsequent diagnostic examination. It needs to be clear that the purpose of screening is not to diagnose a disease, but to screen out people who are more likely to have a disease.

At present, the screening and diagnosis of Down's syndrome, trisomy 18 syndrome and congenital neural tube malformation is such a systematic method. First, for all pregnant women, through the screening method, the pregnant women with high risk of three diseases, such as congenital foolishness and lingual extension dementia, are screened out for the next step of diagnostic examination. If the fetus is finally diagnosed, then There is no effective treatment for these congenital diseases. The better way is to terminate pregnancy.

What is the accuracy of Down's screening?

60-70% of children with Down's disease can be screened by Down's sieve. It needs to be clear that down screen examination can only help to judge the chance of the fetus suffering from Down's disease, but it can not be clear whether the fetus has Down's disease. That is to say, when the blood test index is on the high side, the chance of having baby Tang is higher, but it does not mean that the fetus must have problems. Just like the older pregnant women over 35 have a higher chance of having baby Tang, but it doesn't mean that their fetus must have problems. On the other hand, even if the test index is normal, there is no guarantee that the fetus will not get sick.

If the amniocentesis or chorionic villus test results are normal, the possibility of Down's disease can be ruled out 100%.