Early Down’s test refers to early pregnancy screening for Down’s syndrome. It mainly includes blood test and ultrasound. The test report includes the thickness of the fetal nuchal translucency band (NT) as well as blood test items such as human chorionic gonadotropin (HCG), alpha-fetoprotein (AFP), and chromosome examination.
1.NT: It refers to the thickness of the fluid under the skin of the back of the neck of the fetus measured by ultrasound during the 11th to 14th weeks of pregnancy, which is used to determine the risk of Down’s Syndrome. Usually, the NT value should be less than 2.5 millimeters, and if it is out of the normal range, it suggests that there are abnormalities in the development of the fetus, which should be further examined by amniocentesis.
2. Human chorionic gonadotropin: It is consistently elevated in pregnant women with children born with congenital trisomy, and if HCG is too high in early Down’s test, it suggests that the fetus has an elevated risk of Down’s syndrome.
3. Alpha-fetoprotein: normal fetal AFP level is 1.0MoM, if the pregnant woman’s serum AFP is lower than 1.0MoM, it suggests that Down’s syndrome is positive.
If the early Down’s test report has abnormal results, non-invasive DNA testing or amniocentesis should be performed in a timely manner to further determine the presence of fetal malformations.