Down’s syndrome screening is a method recommended in China for the birth rate of Down’s babies, where blood is drawn at 16-20 weeks of gestation (counting from the first day of the last menstrual period) to presume the chance of the fetus having trisomy 18, trisomy 21, and neural tube defects. Internationally, the timing varies from hospital to hospital, with some hospitals performing early Down’s screening such as blood draws + ultrasound at 11-14 weeks to check the thickness of the posterior zona pellucida of the fetus. Usually blood is drawn at mid-trimester to screen for Down’s syndrome. Time: 16-20 weeks of gestation Steps: The doctor fills in the information of the pregnant woman, please note that the pregnant woman should provide the data of the month and year of birth of the pregnant woman. The pregnant woman will sign and then go to the laboratory on the fourth floor to have her blood drawn (note that an empty stomach is required). The results will be collected by the hospital. Note: 1. The results are affected by the age of the pregnant woman and the week of pregnancy. In order to ensure accurate results, therefore, you must provide your ID card and accurate menstrual status (or can be verified by ultrasound in the second or third trimester of pregnancy) when building your card. If the result has a high risk, then you have a higher chance of having a bad baby and you should go to the hospital for an amniocentesis for further confirmation. If the result is critical, you should go to the hospital for a non-invasive DNA test. If the result is low risk, it just means that the probability of your baby having the disease is low, not that it is absolutely impossible. This is because it is a preliminary screening. 2. The accuracy rate of Down’s syndrome screening is 60 – 80%, and the accuracy rate of non-invasive DNA is 90%, note that neither is 100%. Please understand. It is possible that a patient with a high risk of Down’s syndrome has a healthy baby, or a pregnant woman with a low risk of Down’s syndrome has a baby with Down’s syndrome. 3. You are not forced to have Down’s syndrome screening, you can not do it. But currently 99% of pregnant women do. The state recommends doing it.