What does the Down syndrome screening test for?
Jul 09, 2025
Source: Cainiu Health
Dr. Zhou Xiaofeng
Introduction
The Down syndrome screening primarily targets fetal chromosomal abnormalities. Down syndrome is caused by an extra copy of chromosome 21, while Edwards syndrome results from abnormalities in chromosome 18. These conditions can lead to intellectual disabilities and developmental malformations in the fetus. The screening allows for early risk assessment by measuring maternal serum markers such as alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG).
Generally, Down syndrome screening assesses the risk of the fetus having Down syndrome, trisomy 18 syndrome, and open neural tube defects by testing relevant indicators in the pregnant woman's blood. Detailed analysis is as follows:
Down syndrome screening primarily targets fetal chromosomal abnormalities. Down syndrome (Down syndrome) results from an extra copy of chromosome 21, while trisomy 18 syndrome is caused by abnormalities in chromosome 18. These conditions can lead to intellectual disabilities and developmental malformations in the fetus; screening helps assess the risks in advance.
This test calculates risk values by measuring indicators such as alpha-fetoprotein and human chorionic gonadotropin in the pregnant woman's serum, combined with factors like maternal age and gestational age. Its purpose is to identify high-risk individuals for further diagnostic testing rather than directly diagnosing diseases.
Pregnant women should undergo Down syndrome screening at the appropriate gestational age. If the screening results are abnormal, they should follow medical advice for further examinations and should not become overly anxious or neglect follow-up diagnosis and treatment due to screening results.
