What is the nuchal fold scan?
The nuchal fold scan, also known as the NT is an ultrasound done between 11 and 14 weeks of pregnancy. The ultrasound measures the space at the back of the baby’s neck. Babies with increased risk of Down’s Syndrome and other chromosomal conditions as well as congenital heart conditions have a tendency to accumulate fluid at the back of the neck during the first trimester.  The NT is usually done in conjunction with a blood test known as the first-trimester combined screening.   The blood test measures proteins produced by the placenta, free beta-hCG and PAPP-A (pregnancy associated plasma protein A) both of which are usually higher in babies with Down’s syndrome.

Reasons to consider NT
•The NT can be performed in the first trimester and is less invasive than other screening and diagnostic tests such as CVS (chorionic villus sampling) and amniocentesis.
•Assesses your baby’s risk using a ratio that comes from the results of the ultrasound measurements and blood samples.

Risks of NT
•The NT scan is a specialized ultrasound in which technicians and doctors require special training to use the high resolution ultrasound equipment.
•It is a screening test which gives information on increased risk factors. It does not provide a definitive diagnosis. 
•See risks of ultrasound (above)

Consideration:
I would recommend this test for women who would consider having further diagnostic tests such as CVS or amnio if the results are abnormal.