Prenatal Testing for Down's, Edwards' and Patau Syndrome in London

We offer the SAFE and HARMONY non-invasive prenatal testing (NIPT) in our Wimbledon and Guildford Clinics - Prices start from £350. Evening and Weekend appointments available 

SAFE and HARMONY NIPT tests offer safe and accurate results in 5-7 days.

Are you a mother or father thinking about prenatal testing?

Non Invasive Prenatal Testing (NIPT) is now available for expectant parents considering screening for Down’s, Edwards’ and Patau syndrome.  This test uses a blood sample from the mother and works by analysing the DNA fragments present in the maternal plasma during pregnancy.

The detection rates for NIPT are 99% for Down syndrome, 98% for Edwards syndrome and 80% for Patau syndrome

Where the risk from the NIPT test suggests a high risk the parents will be offered an invasive test to confirm the diagnosis as NIPT is a screening test, not a diagnostic test.

Ms Roberts currently offers the SAFE test and Harmony test (marketed by Ariosa Diagnostics). In all cases, two test tubes of maternal blood are taken and couriered to the laboratories. The SAFE test and the Harmony test are analysed in the UK.

What does the NHS offer?

The National Screening programme offers screening for Down's Syndrome at 11-14 weeks using a combination of ultrasound measurement of nuchal translucency ( the fluid-filled space at the back of the neck) and hormones found in the mother's blood.
The risk is calculated and where the chance is 1 in 150 or more the parents are offered the opportunity to have an invasive test, either a Chorionic Villus Sample or an amniocentesis. Both of these tests carry a risk of a miscarriage of 1 in 100 above the background or natural risk of miscarriage.

The NHS is currently offering NIPT at some hospitals for high risk pregnancies.

Why should I choose Non-Invasive Prenatal Testing (NIPT)?

Many parents choose to have antenatal screening for Down's Syndrome. As mothers get older the risk of having a baby with Down's Syndrome goes up. Screening programmes aim to identify pregnancies at high risk.  Our private clinics in Wimbledon and Guildford offer the Harmony Test and SAFE tests to patients.

These maternal blood tests can identify the majority of pregnancies affected at an early stage without putting the pregnancy at risk of miscarriage. They can identify over 99% of pregnancies affected which provides a more effective screening test than the conventional combined screening test. These prenatal testing options can also identify Edwards and Patau's Syndrome.

Many couples do not wish to put the pregnancy at risk by having an amniocentesis and this safe method of screening can offer reassurance.

What do the prenatal tests involve?

  1. The mother needs to have had an ultrasound scan. This is necessary to date the pregnancy and identify whether it is a twin or singleton pregnancy.
  2. Where there has been an early miscarriage (vanishing twin ) pregnancy the laboratory needs to be aware or the testing process will not be possible.
  3. If the mother has had fertility treatment or egg donation this information is relevant to the choice of test and the process of analysis.
  4. The mother's weight and height are measured and recorded.
  5. After counselling and completion of a consent form, a is a simple blood test is taken, two tubes of blood are collected. The second tube is a 'back- up' in case the analysis of the first tube fails.
  6. The tubes are labelled and sent with the consent form to the USA for analysis.

How will I get my results?

This will be discussed with you at the time of the test.
Results are normally available within 5-7 days. Most mothers opt to receive the results via a telephone call, a hard copy of the results is then sent by post or by a scanned email if you wish.
There is a chance that it will not be possible to obtain a result from either of the blood tubes. In this situation, the laboratory will ask for further samples to be taken. There would be no further charge for this.

How are the results described?

As with the combined screening test the results are given as a probability. It is a screening test and not a diagnostic test.
For example a normal result will show a very low risk of the pregnancy being affected, each Trisomy is expressed separately (e.g. 1 in 10,000 risk for Down's Syndrome). A high risk result might give a risk of 1 in 2 chance of the pregnancy being affected. In this situation, a diagnostic or invasive test would be offered to obtain a definitive answer.

What happens after the test?

Depending on how many weeks pregnant you are, you will still have the opportunity to have a 12 week scan privately or with the NHS. The focus of the 12 week scan will change as you will already have the result of the Downs syndrome test, so the 12 week scan will look at the baby in detail for structural abnormalities (these may exist without a chromosomal abnormality). You will still have the opportunity to have the later scans, such as the 20 weeks scan, as before. If the NIPT is negative then it is important that the person conducting the 12 week scan is aware of this. If the test is positive then you should return to your doctor for further counselling.

Are there problems this test will not detect?

Yes. Structural abnormalities such as Spina Bifida, heart defects and a poorly growing baby will only be seen on scans and often not until later scans. These scans should still be undertaken.

SAFE, Harmony and Prenatal Genetic Test Information

Harmony TestSAFE Test
Available after 10 weeksAvailable from 10 weeks
›99% T21 (Down’s Syndrome)›99% T21 (Down’s Syndrome)
›98% T18 (Edwards Syndrome)›99% T18 (Edwards Syndrome)
80% T13 (Patau’s Syndrome)›99% T13 (Patau’s Syndrome)
Optional analysis of sex chromosome (x,y) conditionsn/a
Optional fetal gender determinationOptional fetal gender determination
Results in 5-7 business daysResults in 3-5 business days
Redraw rate of 5%Redraw rate of less than 1.2%
Less than 0.1% false positive rateLess than 0.1% false positive rate
Fetal fraction % measuredFetal fraction % measured and integrated into risk assessment
Also available in twin, multiples, singleton donor

Available for single and identical twins; including IVF, egg donor and surrogate pregnancies. For non-identical twin test sensitivity is reduced to 95% and above