The nuchal cord is the cord of primitive nervous tissue along the length of a foetus that forms into the spinal cord. A nuchal translucency scan is a form of ultrasound scan that measures the amount of fluid in the nuchal cord in the neck of a foetus between weeks 11 and 14 of pregnancy. An abnormal result indicates a higher risk of the foetus having Down syndrome or other spinal cord defects (eg. spina bifida). It is usually combined with a blood test (triple tests) to measure hormone levels that may also be abnormal in women with a Down syndrome pregnancy. These tests are only indicative and an amniocentesis or chorionic villus sampling is necessary to confirm the diagnosis.
These tests are more commonly performed on older mothers.
Unfortunately, if an abnormality is found, there is no treatment available for the foetus, but the mother is given the option of an abortion.