Patient's question:
Today I went for a prenatal check-up and had the Down syndrome screening. I would like to ask, what is the normal value range for the Down syndrome screening approximately?Doctor's answer:
Down syndrome screening is a preventive test that comprehensively evaluates the risk of giving birth to a fetus with congenital defects by estimating the concentration of key indicators in a pregnant woman's blood, including alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and free estriol, while considering factors such as the gestational age at the time of blood collection. The molecular weight of AFP is 64,000-70,000 daltons, and the average MoM value of free β-hCG is 2.3-2. The normal value of hCG is 1.8-2.3 MoM. In general, if β-hCG is abnormally reduced and ≤0.25 MoM, it indicates a high risk of trisomy 18. Down syndrome screening is primarily performed during the second trimester of pregnancy as a detailed examination, mainly to assess the likelihood of Down syndrome, which serves as a reference value.