What does it mean to do Down syndrome screening during pregnancy?

The awareness of eugenics has now penetrated deeply into the hearts of every couple. In order to give birth to a healthy and smart baby, many couples need to do a variety of tests during pregnancy. For example, Down syndrome screening is a test that many pregnant women need to do during pregnancy. Down syndrome screening is mainly for screening Down syndrome, that is, to check whether the baby will be a congenitally stupid Down syndrome child.

1. What does it mean to do Down syndrome screening during pregnancy?

1. Down syndrome screening test is the general name for prenatal selection tests for Down syndrome. It is a test method that extracts blood cells from pregnant women, tests the concentration of alpha-fetoprotein and human gonadotropin in the mother's blood cells, and calculates the risk of having a child with Down syndrome based on the period of pregnancy, age, weight and the number of weeks of pregnancy when blood was drawn. Down syndrome screening is usually carried out between 15 and 20 weeks of pregnancy, and is best done between 16 and 18 weeks of pregnancy. On the morning of the test, a small amount of blood from the jugular vein should be drawn on an empty stomach. You can eat after the blood test.

2. Down syndrome screening is a test to select the possibility of a fetus suffering from Down syndrome. It is usually done by drawing blood at 16-20 weeks of pregnancy. The test requires fasting. The result is not a final diagnosis, but only a risk factor, with an accuracy of between 70-80%. Doctors generally recommend that you agree to the test, but it is not necessary. It is best for older pregnant women to do it. I suggest that there is no need to do this. If you take high-risk measures, it will continue to increase the psychological burden on pregnant women. You only need to have a four-dimensional color ultrasound to screen for fetal abnormalities during the 22nd to 26th week of pregnancy.

3. Some pregnant mothers object to Down syndrome screening, thinking that the results of Down syndrome screening cannot accurately determine whether the baby is mentally retarded. However, after all, it is the most economical, simple and harmless test method for determining whether the baby is mentally retarded. If the result is abnormal, amniocentesis can be performed further. Pregnant mothers may ask, since the accuracy of Down syndrome screening is not high, why not do amniocentesis immediately? Because amniocentesis is relatively risky, it is not recommended unless it is necessary, and the cost is also high.

2. Types of Down syndrome screening

1. Initial Down syndrome screening

Down syndrome screening in early pregnancy is a combination of nuchal translucency (NT) screening with B-ultrasound examination and blood cell biochemical examination results to conduct a risk assessment on the possibility of a fetus with sex chromosome genetic diseases in expectant mothers. Early Down syndrome screening can detect a very high proportion of Down syndrome and other chromosomal abnormalities, but because the accuracy of the nuchal translucency scanner is determined by many factors, including the level of the ultrasound physician and the accuracy of the scanner used, early pregnancy Down syndrome screening still has certain defects. If Down syndrome screening fails in the early stage, you can do nothing or do related tests for diagnosis, such as amniocentesis, for a more detailed diagnosis.

2. Mid- to late-stage Down syndrome screening

The mid-pregnancy Down syndrome screening involves extracting blood cells from maternal and infant products to test the concentrations of alpha-fetoprotein (AFP) and human gonadotropin (hCG) in the mother's blood cells, as well as free estriol (uE3) and inhibin A. The risk of having a child with Down syndrome is calculated based on the increase or decrease of these markers in the pregnant woman's blood cells and combined with the pregnant woman's date of birth, age, weight and gestational age at the time of blood collection. When high-risk conditions are found in the middle and late stages of Down syndrome screening, fetal abnormality screening and amniocentesis can be performed.