Question
At 13 weeks, the NT test result was 1.3mm, and at 16 weeks, the Down syndrome test result was 1:499. Is this a big issue?? Is the risk of Down syndrome higher? Do I need to take more tests? I’m 25 years old, and I hope doctors can help me out. I’m really worried.
Answer
Case Analysis: Down syndrome, also known as Trisomy 21, refers to a condition where the patient has an extra chromosome on the 21st pair (normal people have a pair). The Down syndrome screening is conducted by measuring the levels of AFP and HCG in the pregnant woman’s serum, combined with her age, weight, and gestational age to calculate the risk value. The critical value is 1/275. Values above this indicate high risk, while those below are considered low risk. The incidence rate of Down syndrome (DS) in the general population (under 37 years old) is 1/750. Guidance: The purpose of the Down syndrome screening is to determine the risk of the fetus having Down syndrome by analyzing the pregnant woman’s blood. If the results of the screening show a higher risk of the fetus having Down syndrome, further confirmatory tests should be conducted – amniocentesis or chorionic villus sampling.