Frequently Asked Questions
WHAT IS NIPT?
NIPT is a term used for a method of genetic screening used in antenatal screening, used to screen circulating free DNA (cfDNA) which can be found in a sample of a mother’s blood. It examines DNA in the chromosomes that originate from a baby and with today’s technology it is used to identify the risk of whether you are at an increased risk of giving birth to a child with a genetic disorder. There are 2 chromosomes in a set and a person usually has 46 sets of chromosomes, 23 sets from the mother and 23 sets from the father. NIPT can detect where there are extra chromosomes ie with Downs Syndrome or only one of a set as with Turners Syndrome.
WHO ARE TESTS SUITABLE FOR?
NIPT tests are suitable for pregnant women from the 9th or 10th week of pregnancy.
We have tests that are suitable for both single and twin pregnancies (including vanishing twin). Please note the NIPT test will analyse the chance of an affected result for the pregnancy, but will not be able to provide a twin-specific chance.
The test is suitable for pregnancies achieved by IVF techniques, including gamets donation.
The test is suitable for surrogate pregnancies.
Gender determination can only report if a Y chromosome is or is not present. It will not identify which twin or if both twins are male.
NIPT involves a quick blood sample from the arm, making it safe and easy for you and your baby. Your sample is then sent to a laboratory where a technician will look at the DNA in your blood for signs of genetic abnormalities. Once the result of your test is analysed the laboratory will determine whether you are placed in the LOWER or HIGHER chance category. This can be used to indicate whether further diagnostic testing should be taken to confirm the result. Result times can vary between 3-10 working days depending on the test chosen and the analysis method of the test. ALL TRIMESTER test results are delivered personally to you by a medical professional.
WHEN CAN NIPT TESTS BE PERFORMED?
Trimester ONE NIPT test is available from 9 week’s gestation. All other NIPT’s can be performed any time after 10 weeks — this is earlier than any other antenatal screening or diagnostic test.
NHS antenatal screening;
Nuchal translucency scanning: between 11 and 13 weeks
CVS: 10 to 13 weeks
Quad screen: between 14 and 22 weeks
Amniocentesis usually performed between 16 and 18 weeks & sometimes as early as 13 or 14 weeks or as late as 23 or 24 weeks
THE ACCURACY OF NIPT
NIPT tests create less false alarms than standard NHS first-trimester blood screenings (like first-trimester bloodwork or quad screening). Research has shown that NIPT is much more accurate than those same standard screenings in predicting the risk of chromosomal abnormalities. Because of the high rates of false 'positive' from NHS combined screening, many women are often referred to us from our NHS colleagues when they receive a 'higher chance' combined result. Some hospital offer NIPT privately themselves for a similar fee, however they do not include gender determination AND take much longer to report the results back to you. Contact us for further information on the test you have chosen.
'HIGHER CHANCE' RESULTS
In the event of a 'higher chance' NIPT result we make a medical referral to your local fetal medicine team who will help you to decide the next steps forward, including whether to have a fully diagnostic test like Chorionic Villus Sampling (CVS) or amniocentesis (“amnio”). Both tests analyze a baby’s own genetic material, collected from the amniotic fluid or placenta to tell with 100 percent certainty whether a baby actually has a chromosome abnormality. However, these tests are invasive, which means they slightly increase the chance of miscarriage approx 2% for Chrorionic Villus Sampling (CVS) nationally ie. approximately 1 in every 50 women, and 1% increase for Amniocentesis, which is 1 in every 100 women who have the procedure.
WHEN IS NIPT NOT SUITABLE?
NIPT is not suitable if you have been diagnosed with cancer or know that you have chromosomal abnormalities including Trisomy 13, 18 and 21.
NIPT cannot be performed if you have had an organ transplant or received stem cell therapy or immunotherapy within the last 12 months.
NIPT cannot be performed if you have had a blood transfusion with the last 3 months.
WHAT IS A FAILED RESULT
This means that it has not been possible to produce a result. In a small number of cases (less than 0.1%)* it is possible that there is not enough cFDNA from your baby present in your blood (Fetal Fraction) to produce the result. The laboratory will request a second sample at no additional cost. However, you may be asked to pay for the Phlebotomy appointment if one is required.
Please note: A failed test result will only be reported after comprehensive testing of your sample. * Dependent on the test you have chosen