Nuchal translucency is the name for the fluid behind the neck of your baby.
Normal babies will accumulate fluid under the skin behind the head and neck between 9 and 14 weeks of pregnancy, however excess fluid has been associated with chromosome abnormalities such as Down syndrome.
We use ultrasound as a way to measure the size of the nuchal fold at the back of your baby’s neck, it is a simple ultrasound, and should be performed between 11 and 13 weeks.
The Nuchal Translucency (NT) tends to be larger in a baby that might be affected by a chromosome abnormality and it can be compared with what is expected for a baby of the same size (NT Normal Range).
Along with assessing the Nuchal Fold of your baby, we also offer our comprehensive assessment, which we call “NT-Plus”, this involves:
- Your age
- Blood sample
- 11-13 week anatomy scan of your baby.
We take a blood sample from you so that we can measure the quantities of two proteins in your blood (free-BhCG and PAPP-A). The assessment of these elements (age, blood, scan) combined give us a comprehensive understanding of the likelihood of your baby being affected by a chromosome abnormality.
Why do you need to take a blood sample?
There are two proteins in a mothers blood that we measure:
- PAPP-A (Pregnancy associated plasma protein-A)
- BhCG (Beta human chorionic gonadotrophin)
The levels can be assessed from a simple blood test taken from you either before or on the same day as the Nuchal Translucency ultrasound is performed. The results can be compared to the expected results in a pregnancy at the same gestational age. Simply by adding this blood test to the screening process, increases the detection rate from 80% up to 90%. This additional 10% detection means that half of the Down syndrome affected pregnancies that are not being detected by your age and Nuchal Translucency alone, are now able to be detected by including the additional information from the blood test.
Blood tests are to be done a week prior to the ultrasound at a pathology collection centre of your choice.
Why should I have an anatomy scan at the same time?
We recommend having your 11 – 13 week scan at the same time, there are many benefits to this scan including:
- Accurate dating of your pregnancy
- Diagnosis of multiple pregnancy
- Detection of early pregnancy failure
- Early assessment of your baby’s structure (such as their brain, limbs and abdominal wall)
- Detection of some of the more severe structural abnormalities, if any.
What if my results show an increased risk?
If your results indicate that you have an increased risk of a baby with a chromosome abnormality, you will be offered further prenatal testing. Typically Chorionic Villous Sampling (CVS) or Amniocentesis will be offered to you, at Sydney Ultrasound for Women, our doctors are fetal medicine sub specialists (MFM, COGU) and therefore our CVS and Amniocentesis procedures deliver excellent results.
Remember, any woman who falls pregnant can have a child with a chromosome problem, but the risk increases with age.
For more information on Nuchal Translucency (NT), as well as our comprehensive assessment NT – plus, please get in touch with us.