Nuchal Translucency Scan

On the day

When you visit Adelaide Women’s Imaging for a nuchal translucency scan you will be greeted by one of our friendly reception staff.

A sonographer will then collect you from our reception area and take you to the ultrasound room. You may need to change into a medical gown for your procedure.

Once the sonographer has taken an initial set of images, they will be reviewed by the obstetrician/gynaecologist. On many occasions the doctor will then also perform a brief ultrasound assessment. Wherever possible, you will be given feedback regarding results at the time of the scan.

FAQs

What happens to the increased nuchal translucency with advancing pregnancy?

In the majority of patients this disappears and is not visible at the routine 18-20 week ultrasound. This explains why it is important that the scan be performed around 11-14 weeks i.e. there is only a narrow window of opportunity when this ultrasound marker of chromosomal abnormality is evident.

What is the risk of the scan?

Transabdominal and transvaginal ultrasound examinations are a safe investigation at all stages of pregnancy.

A Nuchal Transluency (NT) - Obstetric Ultrasound scan at 11-14 weeks (in the first trimester of pregnancy) provides an opportunity to assess the anatomy of the baby. During the examination many parts the fetal anatomy will be pointed out to you. It is also an opportunity to determine the number of babies present and the baby's heart rate.

NT scans are currently the most accurate non-invasive test for detecting Down syndrome during pregnancy.

It combines maternal age with high-resolution ultrasound assessment of fetal NT and the levels of two proteins (free-BhCG and PAPP-A) in a pregnant woman's blood.

Normal fetuses accumulate fluid under the skin behind the head and neck between 9 and 14 weeks of pregnancy. The NT tends to be larger in a fetus affected by a chromosome abnormality, such as Down Syndrome and it can be compared with what is expected for a fetus of the same size (NT Normal Range).

Preparation

Please empty your bladder two hours before the examination time. Then slowly drink 600ml of water to fill your bladder and keep it full for your examination.

Procedure

You may be asked to change into a gown, but you will be covered during your examination except for the area required to be examined. A layer of warmed gel will be spread over the area to be examined to facilitate good contact as this helps to produce the best possible images. The ultrasound transducer is then placed over the area to be investigated.

Occasionally, the scan may need to be performed through the vagina (transvaginal imaging). In these circumstances a very narrow ultrasound probe is gently placed a short distance into the vagina and the ultrasound beam directed towards the baby. With this approach greater detail may be obtained of the fetal anatomy.