Nuchal translucency is a collection of fluid naturally found under the skin of a baby’s neck. In the majority of babies with Down’s Syndrome, nuchal translucency is increased and can be detected with a simple ultrasound scan. A nuchal translucency test is best carried out when you’re 10-14 weeks pregnant. This is because before 10 weeks your baby will be too tiny to test and after 14 weeks your baby’s developing lymphatic system is likely to start absorbing excess fluid.
The test is a screening test, rather than a diagnostic test, and will show the likelihood of your baby having Down’s Syndrome. The good thing about nuchal translucency scanning is that it is safe for both you and your baby and can help you to decide whether or not to have a diagnostic test, such as amniocentesis, which will give you a definite diagnosis but also carries a small risk of miscarriage. For example, if your scan shows your baby is at low risk of having Down’s Syndrome, it may help you to feel at ease and decide against further testing, although we’d recommend that you discuss your decision with your GP, midwife or consultant.
The scan is exactly like having a traditional ultrasound scan, although occasionally we may recommend a vaginal scan, which will give us a better view of your baby. In many cases, a nuchal translucency scan can also help to rule out other major abnormalities and you’ll be able to see your baby’s head, spine, limbs, hands and feet.