The nuchal fold scan is an ultrasound scan, usually performed at 11-14 weeks. It is the most accurate way of estimating the risk of the fetus having Down’s syndrome or other chromosomal disorders. It differs from the dating scan in that what’s being measured here is ‘nuchal translucency’, or the fluid accumulation in the neck of the fetus. This measurement, can indicate the likelihood of your baby having Down’s syndrome, and indicate whether further tests would be necessary.
What do the results mean?
Your personal risk factor will also take the the following into account:
Age of the mother(risk of having a baby with Down’s syndrome increases with age)
Presence or absence of the fetal nasal bone
Leakiness in the tricuspid valve
Presence or absence of any physical abnormalities
Level of two hormones (ßhCG & PAPPA) in the mother’s blood
A risk factor of one in 250 or less is considered high.
Why screen like this?
The biggest advantage of this type of scan is that it’s a non-invasive means of diagnosing chromosomal abnormalities, and therefore carries no risks to mother or baby, unlike CVS or amniocentesis. Also, as it is carried out relatively early in pregnancy, there is plenty of time to make further investigations and, should the news be bad and you decide on a termination, this procedure is much more straightforward at this stage of pregnancy.
The nuchal scan is only offered on the NHS to 7 per cent of women, whether you are one of the lucky ones is a bit of a postcode lottery. It’s certainly worth checking what’s available in your area and asking for a referral, especially if you are in the older, higher risk category (over 35). But don’t delay, as this test can only be performed relatively early in pregnancy.
If your GP or hospital do not offer the scan, contact the Fetal Medicine Centre (www.fetalmedicine.com) to find an accredited centre near you that can do it privately (it will cost £90-£150).