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More information on Nuchal Transluency 

A Nuchal Translucency Scan is performed between 11weeks – 13 weeks, 6 days of gestation. We like to see our patients around 12 weeks plus so ossification of nasal bone has occurred for nasal bone assessment. Nasal bones are absent in Down’s syndrome babies. At Paradise Ultrasound all our sonographers have been accredited for the NB. Nuchal Translucency is measure by the amount of fluid that accumulates under the skin behind the baby’s head and neck. Too much fluid in this space has been associated with chromosome abnormalities such as Down’s Syndrome (Tri21)

A blood test is required to be done 3-5 days before the appointment. It measures two chemicals that are produced by the placenta and across into your bloodstream Papp A (Pregnancy – associated plasma protein) and Bhcg (Human chorionic gonadrotropin). Foetuses with chromosomal abnormalities have low Papp-A values.

Values lower than 0.4mm increase the Risk of chromosomal abnormalities. Foetus with Bhcg higher than 2.5mon is indicating the increased Risk of Trisomy 21 (Down ’s syndrome). In Trisomies 13 and 18 the value of Bhcg are generally low and are suspicious when the values below 0.4moms

Just remember these are reference values used to calculate the probabilities of chromosomal anomaly or Risk. A combination of your age, the size of the baby, the thickness of Nuchal translucency measurement, the Nasal bone assessment and the levels of blood chemicals allows us to calculate a Risk estimate for Down’s Syndrome in this pregnancy.

A Calculated Risk less than 1 in 300 suggests a low Risk for Down’s syndrome in this pregnancy. As not all foetuses with chromosome abnormalities can be detected by this screening test, a low Risk result is not the same as No Risk. A risk estimate of greater than 1 in 300 is considered an increased risk for Down’s syndrome but it Does Not mean that the baby will definitely have the condition. You will be counselled about the result and whether you wish to proceed to further prenatal testing (by NIPT, Chorionic Villi Sampling or Amniocentesis).

Open Spina bifida screen at 12 weeks

All patients having the 12 week Nuchal Translucency Scan at Paradise Ultrasound will also have Spina bifida screening done at the same time. At 12 weeks the foetus with open Spina bifida develop changes in the back of the fetal brain. The fourth Ventricle or “Intracranial Translucency” is obliterated. By demonstrating the normal Intracranial Translucency (IT) significantly reduces risk of Spina bifida and an absence of IT allows for early detection of open Spina bifida.

To be certain your Nuchal Translucency scan is performed correctly it is important that you have your scan performed at an accredited centre, where the sonographers undergo strict auditing by the Fetal Medicine Foundation. 

At Paradise Ultrasound, all of our operators are accredited for the Nuchal Translucency scan and is one of the few practices who have all of their operators N.B accredited as well.

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