11-13 Week Early Anomaly and Nuchal Translucency Ultrasound Scan
At this gestation the fetal head, abdomen and four limbs are formed and the fetus will already be swallowing and excreting the amniotic fluid. It will measure between 45 and 84 mm from its ‘crown’ to its ‘rump’ .
The purpose of this ultrasound scan is to:
Confirm the heartbeat and observe fetal movements
Check for a multiple pregnancy
Measure the fetus and confirm the due date
Examine the anatomy of the fetus to exclude major structural defects
Measure the Nuchal Translucency to screen for Down Syndrome
Nuchal Translucency Scan
This scan is a simple and effective way of screening for major chromosomal abnormalities such as Down Syndrome and it will detect around 80% of affected pregnancies.
From an image on the television monitor, a measurement can be taken of the amount of fluid at the back of the baby’s neck (Nuchal Translucency - sometimes also spelt "Nucal"). A risk can then be calculated to determine the likelihood of the baby having Down Syndrome. Some babies with Down Syndrome have an absent nasal bone, which is another useful marker in this screening test.
The sonographer will discuss the results of the ultrasound scan fully with you after the scan and if appropriate, will give you information on invasive testing.
Note that 95% of patients will have a low risk result requiring no further investigation, other than the routine 22 week detailed anomaly ultrasound scan.
At every pregnancy ultrasound scan, you will be offered images of your baby at no extra cost.N.B. All centres offering the Nuchal Translucency scan must be approved by the Fetal Medicine Foundation (FMF) in London. St Peter’s Hospital, in Surrey, was the first District General Hospital in the country to set up this screening test in conjunction with the FMF, and our sonographers have over 10 years experience in this technique.
