More about Nuchal Translucency

Presence or absence of the nasal bone

Absence of this bone is associated with an increased risk of an underlying chromosome anomaly.

This information is used to calculate the risk of chromosome abnormalities. Nuchal translucency measurement is most accurate when used in conjunction with a maternal blood test which estimates hormones produced by the placenta (afterbirth) and baby. These hormones are called free Beta human chorionic gonadotrophin (βHCG) and PAPP-A (pregnancy associated plasma protein A).

It is important to realise Nuchal Translucency screening gives you a ‘relative risk’ value for the baby having chromosomal anomalies, such as Down’s syndrome. In the great majority of cases, we hope that this will be reassuring. The only way to be certain is to have an invasive test, Amniocentesis or Chorion Villus Sampling (CVS) which carry a small risk of miscarriage and this is only usually offered if the risk is greater than 1 in 250.

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