1. Down's screening is an index that can only be checked between pregnancy 15-2 1 week. It is mainly to detect the probability of the baby suffering from Down syndrome. Can only be used as a reference, not accurate. And this kind of examination also allows the doctor to decide whether you need this kind of examination according to your physical condition. Only a blood test is needed during the examination, which is usually carried out at the same time as other blood tests. Then cooperate with your recent B-ultrasound to determine the baby's risk. If you are young and healthy, doctors will hardly force you to recommend you. Of course, if you are not at ease, you can also ask for it yourself.
2. This is Cha 2 1- trisomy syndrome, a congenital idiot, and it is Cha gestational age 14- 19 blood. This inspection is voluntary participation and informed choice. It's related to age. With the increase of pregnant women's age, the birth rate of children with Down syndrome has increased rapidly. The birth rate is 3‰ at the age of 30, 6‰ at the age of 35, and 16‰ at the age of 40. Therefore, it is generally recommended that pregnant women over 35 years old do amniotic fluid chromosome analysis. Because most women are pregnant and give birth under the age of 35, only 20% of children with Down syndrome are born to women over 35. Therefore, screening pregnant women under the age of 35 can achieve the goal of reducing the birth of sick children as much as possible. Of course, screening is not the same as diagnosis, and there may be a few false positives and false negatives. For the final diagnosis of high-risk pregnant women, amniocentesis is needed for amniotic fluid chromosome examination.
Ultrasound examination plays an important role in prenatal screening of fetal malformation. For a long time, it has been widely used in prenatal screening and diagnosis of severe limb deformities. Ultrasound can also detect many signs of fetal congenital malformation and some rare fetal malformations. High-resolution ultrasound images can further provide fetal anatomical information. Therefore, ultrasound examination is one of the main means to screen congenital malformation. Not only that, ultrasound images can also correct the gestational age and know whether there are multiple pregnancies and stillbirths. It can obviously improve the accuracy of serum biochemical screening for pregnant women.
Therefore, if conditions permit, it is best to do four-dimensional color Doppler screening at 22-26 weeks of pregnancy.
3. Down syndrome, also known as 2 1 trisomy, means that patients have one more chromosome 2 1 than normal people (normal people are a pair). Down's screening is a risk value calculated by the content of AFP and HCG in pregnant women's serum, combined with the age, weight and gestational age of pregnant women. The critical value is 1/275. Greater than is high risk, less than is low risk. The probability of Down syndrome (DS) in the general population (under 37 years old) is 1/750.
If the screening result is high-risk, it is recommended to do amniocentesis, but even if it is high-risk, it is not necessarily Down syndrome, but to be on the safe side, it is recommended to do DS screening!
Tang screening is short for prenatal screening. The purpose is to judge the risk of Down syndrome in the fetus by detecting the blood of pregnant women. If the results of screening in early Tang Dynasty show that the risk of Down's syndrome is high, further diagnostic examination-amniocentesis or chorionic villus examination should be carried out.
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5) How to check the test results?
At present, the screening test for Down's syndrome is to accurately calculate the risk of each pregnant woman's Down's syndrome fetus by detecting the concentrations of alpha-fetoprotein (AFP) and human chorionic gonadotropin (β-hCG) in the blood of pregnant women and combining with the age of pregnant women.
The normal value of alpha-fetoprotein should be greater than 2.5MoM, and the lower the detection value, the higher the probability of fetal down syndrome. The higher the chorionic gonadotropin, the higher the risk of Down syndrome in the fetus. In addition, the doctor will also input the pregnant woman's alpha-fetoprotein value, chorionic gonadotropin value, age, weight and weeks of pregnancy into the computer, and the computer will calculate the risk of Down's syndrome in the fetus. If the test results show that the risk is lower than 1/270, it means that the risk is relatively low, and the probability of down syndrome in the fetus is less than 1%. However, if the risk is higher than 1/270, it means that the risk of fetal illness is high, and amniocentesis or chorionic villus examination should be further done.
6) What is the screening accuracy of Tang?
Down syndrome screening can screen 60-70% of children with Down syndrome. It needs to be clear that the screening test can only help to judge the probability of Down's syndrome in the fetus, but can't determine whether the fetus has Down's syndrome. In other words, when the blood test index is high, the chances of having a "Tang" baby are higher, but it does not mean that there must be something wrong with the fetus. Just as an elderly pregnant woman over the age of 35 is more likely to give birth to a "Tang" baby, it does not mean that there must be something wrong with the fetus. On the other hand, even if the detection index is normal, there is no guarantee that the fetus will not get sick.
Pregnant women whose Tang screening test index exceeds normal should undergo amniocentesis or chorionic villus examination. If the results of amniocentesis or chorionic villus examination are normal, the possibility of Down syndrome can be completely ruled out.
If you have any questions about Down's screening results, it is recommended to go to the top three hospitals for review! May you have a healthy baby!