What is Down's Syndrome and Nuchal scan - your risk explained

All women, whatever their age, have a small risk of delivering a baby with a physical and/or mental handicap.  In some cases the handicap is due to a chromosomal abnormality in which there is an extra chromosome 21 (Trisomy 21).

Down's syndrome is one of the most common genetic abnormalities affecting 1 in every 700 births worldwide with the risk increasing with maternal age. In modern western societies, the average age at which a woman has her first child is on the increase (approximately 29.7 years).

Down's syndrome (DS) and Fetal anomaly screening is a high priority issue with parents.  Increasingly parents expect modern antenatal care to include up to date information and the best available screening and diagnosis for their unborn baby. Currently Nuchal ultrasound scanning and blood testing for DS is not widely available at the routine antenatal booking visit. Many women choose to have an invasive test, such as amniocentesis (based on maternal age), taking on the risk of miscarriage, without being given the information about effective non-invasive methods of screening.  

Nuchal Scan

Recently the National Institute for Clinical Excellence (NICE) have recommended Nuchal Translucency Screening (Ultrasound scan assessment of neck soft tissue thickness) with First Trimester Biochemistry as the test with the best efficiency of detecting DS (90% as compared to 65% with second trimester serum screening). This early nuchal scan also has the advantage of detecting other major fetal anomalies at an early stage of pregnancy.

Your Risk of Down's Syndrome

The risk of chromosomal defects like Trisomy 21 increases with maternal age and if the couple have already produced a child with Down's syndrome. However the majority of babies with DS are born to healthy young parents without any known risk.

Picutured above is a nuchal scan of a 12-weeks fetus showing a normal nuchal translucency and nasal bone.

Nuchal scans in London, Manchester, Liverpool, Bradford 

Combined first trimester screening for Down's syndrome

In the future, the National Institute for Clinical Excellence (NICE) would like all women to be offered first trimester screening for Down's syndrome, with a test that has a high detection rate and a low false positive rate - a nuchal scan This would reduce the number of women who go on to have invasive tests unnecessarily.

In an ideal world early screening with a nuchal scan is what you should be offered. Unfortunately during the first three months of pregnancy (first trimester) screening is not available through the NHS in many areas of the country and generally, when it is available, uses only a nuchal scan in isolation and doesn’t offer it combined with a blood test.

The advantages of a private combined Down’s screen (nuchal scan and blood testing) with Baby Premier are:

• No waiting lists. First trimester screening for Down's syndrome must be carried out between 11 weeks and 13 weeks + 6 days of gestation, therefore waiting is not an option.
• You choose the appointment time to suit your own convenience.
• High detection rates. We perform combined testing with a nuchal scan and blood testing, to achieve a detection rate of over 90 per cent.
• Immediate results and advice. The process takes less than 2 hours.
• No risk to your baby - the nuchal scan is non-invasive.
• Because the test is done in early pregnancy you have time to make an informed choice about what you want to do next if you are found to be at high risk for Down's. Your options include doing nothing or having a diagnostic test, such as Chorionic Villus Sampling (CVS) or amniocentesis, both of which carry a small risk of miscarriage.
  
• Peace of mind. It is better to know whether or not there is any risk to your baby as soon as possible, to avoid any unnecessary worry.

See the pages in this section for more information on:

• What tests are available and their accuracy
• Why consider screening
• OSCAR explained and what to expect
• Other advantages of ultrasound scanning in early pregnancy

At  Baby Premier - Specialist Medical Imaging (SMI) we provide a comprehensive service to assess the risk of your baby having Down's Syndrome - Combined testing with nuchal scan and blood testing is far more accurate than nuchal scan on its own. 

How do I arrange an appointment?

Phone 0845 345 7262 to discuss any issues with one of our medical advisers or to arrange a convenient appointment.