The chances of having a Down’s syndrome baby with Down’s syndrome are relatively low with Down’s screening critical risk, but the possibility of having a Down’s syndrome baby cannot be ruled out. Down screening is a method of calculating the risk factor for the presence of Down’s syndrome in a fetus by taking peripheral blood from a pregnant woman at 15+3 to 20 weeks, based on relevant data such as maternal age, gestational week, weight, and fetal biparietal diameter. There are low risk, critical risk and high risk of Down’s syndrome. The Down’s syndrome test is only a preliminary screening test and cannot confirm the diagnosis of Down’s syndrome. Only when the Down’s syndrome test shows a critical risk or high risk, further non-invasive DNA or amniocentesis is needed to make a clear diagnosis. However, not all critical risk or high risk through non-invasive DNA testing, or do amniocentesis test will necessarily appear Down’s baby, most critical risk through the test, and did not occur Down’s baby. The chances of a Down’s baby occurring at critical risk are very low, but it is important to do a good review to rule out the possibility of a Down’s baby, and it is recommended that you seek further medical attention to confirm the diagnosis.