What are normal and abnormal nuchal translucency measurements?

In babies with chromosomal abnormalities, heart defects and many genetic syndromes, the nuchal translucency is thicker. Nuchal translucency measurements are classified as follows:

Normal nuchal translucency:

- 2mm for a baby at 11 weeks.

- Under 2.5mm for a baby at 12 weeks.

- 2.8mm for a baby at 13 weeks.

Abnormal nuchal translucency:

- Nuchal translucency over 3mm: Risk of Down syndrome.

- Nuchal translucency of 6mm: The baby is at risk of Down syndrome as well as other birth defects.

- Nuchal translucency of 3.2 – 3.5mm: High likelihood of the baby having Down syndrome.

Note that the nuchal translucency ultrasound only correctly identifies 75% of the risk of Down syndrome. Depending on the nuchal translucency result, you may need further non-invasive screening tests such as NIPT, the Triple test or the Double test, or invasive testing such as amniocentesis for a more accurate diagnosis.

Reference: hongngochospital.vn