The Down screening test for pregnant women with a critical risk may be problematic and usually indicates that the fetus has some probability of having a chromosomal disorder, which may be abnormal or normal. Down screening, also commonly referred to as Down’s syndrome screening, generally checks for the probability of having trisomy 21-trimester, trisomy 18-trimester and open neural tube defects, and is a risk assessment. The results are low risk, critical risk and high risk. Critical risk generally means between high risk and low risk, which is an intermediate risk, and may have chromosomal abnormality problems or may be normal. Down’s syndrome screening is affected by various factors, the accuracy rate is only about 60% to 70%, so it can only help to assist in determining the probability of a fetus having a disease such as trisomy 21-trisomy, trisomy 18-trisomy, etc., but it cannot confirm the diagnosis. When a critical risk or high risk of Down’s syndrome is detected, tests such as non-invasive DNA or amniocentesis are needed to further assess whether the fetus has a chromosomal abnormality. In case of Down’s syndrome critical risk, it is recommended to visit the prenatal diagnostic center of your local hospital for further tests to comprehensively evaluate the fetus.