Fetuses with Down syndrome are not exclusive to older pregnant women. Although pregnant women over 35 years old are closely related to Down syndrome, the older they are, the greater the chance of giving birth to a child with Down syndrome. However, younger women may also give birth to children with Down syndrome, and only 20% of Down syndrome occurs in older pregnant women. The other 80% of fetuses with Down syndrome are born to young pregnant women under 35 years old. Therefore, it is not possible to prevent Down syndrome if only older pregnant women receive examinations.
But on the other hand, if all pregnant women undergo amniocentesis or chorionic villus examination, it will not only be more expensive, but also increase the chance of miscarriage, so there is no need for all women to undergo amniocentesis or chorionic villus examination. examine. At present, the best way to prevent Down syndrome is to have all young pregnant women undergo Down syndrome screening. Pregnant women who are shown to be at high risk will undergo amniocentesis or chorionic villus examination to determine whether the fetal chromosomes are normal. Have Down syndrome.
Which women need Tang screening?
All young pregnant women under the age of 34 should undergo Tang screening examination. The examination can be carried out between 15 and 20 weeks of pregnancy, preferably between 16 and 18 weeks. Pregnant women who are over 34 years old, women who have Down syndrome in their families, and women who have given birth to children with Down syndrome are already at high risk, so they do not need to undergo a Down screening test, but should do an amniotic membrane test directly. Puncture examination or villus examination.
Is there any danger in folding tang screen examination?
The Tang screening test is a safe and convenient test that is not dangerous to pregnant women or fetuses. The test is based on testing the concentration of alpha-fetoprotein (AFP) and human chorionic gonadotropin (β-hCG) in the blood of pregnant women, so pregnant women only need to draw a little blood for the test without risk.
How to check the test results on Fold?
At present, Tang screening tests test the concentrations of alpha-fetoprotein (AFP) and human chorionic gonadotropin (β-hCG) in the blood of pregnant women. Combined with the age of the pregnant woman, a computer is used to accurately calculate each Risks to a pregnant woman carrying a fetus with Down syndrome. The normal value of alpha-fetoprotein should be greater than 2.5MoM. The lower the test value, the higher the chance of the fetus having Down syndrome. The higher the chorionic gonadotropin level, the higher the chance of the fetus having Down syndrome. In addition, the doctor will also input the alpha-fetoprotein value, chorionic gonadotropin value, and the pregnant woman's age, weight, and weeks of pregnancy into the computer, and the computer will calculate the risk of the fetus having Down syndrome. If the test results show that the risk is lower than 1/270 means that the risk is relatively low, and the chance of the fetus developing Down syndrome is less than 1%. However, if the risk is higher than 1/270, it means that the risk of fetal disease is higher, and further amniocentesis or chorionic villus examination should be performed.
What is the accuracy of the folding Tang sieve?
Down screening examination can detect 60 to 70% of children with Down syndrome. What needs to be made clear is that the Down screening test can only help determine the chance of the fetus having Down syndrome, but it cannot determine whether the fetus has Down syndrome. In other words, when the blood test index is high, the chance of having a Tang baby is higher, but it does not mean that there is definitely something wrong with the fetus. For example, pregnant women over 35 years old have a higher chance of having a Tang baby, but it does not mean that their fetuses must have problems. On the other hand, even if the laboratory index is normal, there is no guarantee that the fetus will not be sick.
Pregnant women whose Down syndrome test index exceeds the normal level should undergo amniocentesis or chorionic villus examination. If the amniocentesis or chorionic villus examination results are normal, the possibility of Down syndrome can be 100% ruled out.
With the continuous development of technology, in addition to Down syndrome screening, non-invasive prenatal genetic testing for Down syndrome and chromosome abnormalities 18 and 13 can now be used. Non-invasive prenatal genetic testing can detect more than 99% of children with Down syndrome. Like Tang screening, you only need to draw blood from your arm for testing, avoiding the increased risk of miscarriage caused by amniocentesis or chorionic villus testing. Non-invasive prenatal genetic testing is another new option for amniocentesis for elderly and high-risk pregnant women. For ordinary pregnant women, non-invasive prenatal genetic testing can also be used as a better screening method.