Is NT a Down syndrome screening test?

Whenever a woman becomes pregnant, she has to undergo many examinations during pregnancy to ensure that the fetus is developing healthily and has no deformities, so as to ensure that the fetus is normal during delivery. Among various pregnancy tests, NT test and Down syndrome screening test are important items. Many people think that these two tests are the same. So, is NT a Down syndrome screening test?

The difference between Down syndrome screening and NT

1. Down syndrome screening generally refers to blood test

The NT value refers to the thickness of the nuchal translucency. This data is detected in the B-ultrasound around 11-13 weeks of pregnancy and is used to assess the risk of Down syndrome. Generally, an NT value less than 2.9mm is normal. If it is higher than 2.9mm, the possibility of Down syndrome should be considered. Combined with the serum test for sugar screening, it is decided whether amniocentesis is needed to determine whether the fetus is Down syndrome.

2. NT screening refers to the thickness of the nuchal translucency and the serum test of pregnant women

The nuchal translucency refers to the space where water accumulates under the skin behind the fetus' neck. During an ultrasound scan, the doctor will measure the thickness of the space between the skin and tissue in detail. The nuchal translucency will be significantly thickened in fetuses with chromosomal abnormalities, especially in babies with Down syndrome.

Down syndrome is usually more likely to occur in older mothers. Medical literature has confirmed that the thicker the nuchal translucency of the fetus, the higher the chance of chromosomal abnormalities. NT screening is performed between 11 and 13 weeks of pregnancy.

3. The time for NT examination is between 11 and 14 weeks of pregnancy. The time for Down syndrome screening examination is divided into early Down syndrome and mid-stage Down syndrome. The time for early Down syndrome examination is similar to that for NT examination, and the time for mid-stage Down syndrome examination is between 15 and 18 weeks of pregnancy. Pregnant mothers can combine NT examination with early Down syndrome screening, so that the examination results will be more accurate.