Wednesday 2 April 2014

What is a Nuchal Scan?

A Nuchal Scan, otherwise known as a Nuchal Translucency (NT) scan, is an ultrasound scan combined with a blood test to screen your baby for the risk of the chromosomal abnormalities such as Down’s Edwards’ and Patau’s syndromes. The screening is offered to all pregnant women but is particularly important for older women who are at greater risk of having a baby with a chromosomal disorder.

Our scan with Sienna at 13 weeks.

What is Nuchal Translucency?
 Nuchal Translucency is a collection of fluid under the skin at the back of the baby’s neck. All babies at around 12 weeks gestation have some fluid at the back of their neck but many babies with Down’s syndrome will have an increased amount of fluid lying under the skin. This fold of skin is also thicker than in babies without Down’s syndrome. An NT ultrasound scan enables your sonographer take a measurement of the skin fold.

What Happens During an NT Scan?
 The nuchal scan must take place between eleven weeks and two days and thirteen weeks and six days of pregnancy, when your baby will measure between 45mm and 84mm. Before this stage, the scan is difficult to perform because your baby is still so small, and after fourteen weeks, any excess fluid may be absorbed by your baby’s developing lymphatic system.

Like with other scans in early pregnancy, you’ll need to attend your nuchal scan with a fairly full bladder, so make sure you drink plenty of water before your appointment. A partially full bladder will push the uterus up, providing a clearer view of your baby.

You’ll be required to expose your abdomen for the scan, but you can keep your underwear on. The sonographer will then place some warm gel onto your stomach to help the scanning probe couple to your skin to obtain a clear image. You will be able to see your baby’s head, spine, limbs, hands and feet on the screen. At this stage some major abnormalities can be detected, however you should still have a detailed anomaly scan at 20 weeks.

Once the relevant skin fold has been detected, measurements will be taken and your sonographer will be able to tell you if the skin fold is within normal range. When your baby measures between 45mm and 84mm, a nuchal translucency of less than 3.5mm is considered normal. If it is not within this range, your results will be discussed, although this does not necessarily mean your baby has Down syndrome. Once you obtain your overall risk result, which is the ultrasound measurement, your age plus the results from your blood test you can decide whether you should have a CVS (Chorionic Villus Sampling) or amniocentesis (at a later date) to obtain a definite result.

CVS and Amniocentesis

These are invasive diagnostic procedures that will give you a definite diagnosis of Down’s syndrome and other abnormalities. A CVS is able to be performed from 12 weeks onwards and an Amniocentesis from 16 weeks onwards. Both of these invasive tests are able to accurately assess whether your unborn has developed a specific genetic abnormality such as Down’s, Edwards’ and Patau’s Syndromes as well as providing a 100% gender identification (if you want to know).

 Are you considering going private for a NuchalScan? Or perhaps you’ve already had your NT scan and you’re looking to have a CVS or amniocentesis to confirm a diagnosis. You’ve come to the right place. The London Ultrasound Centre is able to provide all these services and more. This private scanning service is able to offer specialist care through a team of professional consultants. Call 020 79083878 to book an appointment today.

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