Down’s syndrome screening is usually performed between 3 1/2 and 4 1/2 months of pregnancy, or between 14 and 18 weeks of pregnancy. The test involves taking blood from the mother’s vein and combining it with the ultrasound values of the day, and the results usually appear about 2 weeks after the blood is taken. There is no need to panic if the results of the screening are high risk, as it may mean that the child has a higher chance of developing the disease, but it does not necessarily mean that there is a problem. Further non-invasive DNA testing, or amniocentesis testing, can be done to confirm if there is a problem with the fetus. In addition, if the risk is high, but the NT test done in the early stage, the NT value is less than 3mm, the pregnant mother can basically rest assured, because the NT value will have a higher significance. If you are really not sure, you can do a non-invasive DNA test. Usually, Down’s syndrome screening can detect whether the fetus has neural tube defects and whether the pregnant woman is at high risk for trisomy 18, as well as trisomy 13.