NIPT (Non-Invasive Prenatal Test): Ultrasound Scan and Blood Test
This NIPT scan and blood test is to:
- test cell-free DNA in maternal blood which can indicate the probability of Down's syndrome, Edwards' Syndrome and Patau’s Syndrome (by taking a blood sample and sending it away for testing)
- confirm the viability of your pregnancy by detecting baby’s heartbeat
- determine if it’s a single or multiple pregnancy
- accurately date your pregnancy
Your NIPT test
This pregnancy scan and blood test is performed by one of our qualified sonographers with diagnostic scanning experience.
This scan includes:
taking one sample of blood from your arm
wellbeing check of baby
This means that we check your baby's heartbeat and movement, and if our sonographer spots anything unexpected during this routine check we make sure to advise you appropriately
printed ultrasound images
same-day access to your images and scan report online
results from your blood tests 5 - 7 working days after the lab receives the sample
If the results show a low probability of the chromosomal conditions being tested, you’ll receive a report via email. If the results show a high probability, a specialist member of our team will call you.
If you are expecting twins, we won’t be able to tell you which twin has a high probability of being affected.
We recommend you show your results to your usual healthcare professional. We’ll take their contact details at time of booking if you can provide them, and we can send the results to them free of charge with your consent.
Your NIPT test is analysed in the UK by one of our authorised partners: the NIPT Illumina Test via TDL.
When you book your appointment with us you agree to your personal information being shared with the relevant partners solely for the purpose of this test. We’ll also ask for your express permission during your appointment.
When you book online, depending on your chosen location, you may be contacted to arrange the most convenient way for you to have your NIPT done close by.
We also offer a few extras for free:
we can provide our opinion about the sex of your baby from 16 weeks during the scan (but if you don’t want to know, we’ll keep it hidden). If you’re carrying twins, we can also identify the gender from the scan
if you are under 16 weeks, we'll ask whether you'd like to find out the gender with your blood test results and ensure that it is included in the testing. If you are carrying twins, male test results apply to one or both fetuses and female test results apply to both fetuses.*
you can also spend time viewing your baby live in 4D from 12 weeks, and receive thermal black and white 3D scan prints
as these extras aren’t the primary purpose of the scan, we can’t offer a free rescan if baby is in the wrong position to check
For people over 16 years of age.
*due to the limitations of the test, inaccurate results are possible.
Important information about the NIPT test
No – you cannot have a NIPT test if you
- are carrying more than two babies
- currently have active malignant cancer
- are currently undergoing radiotherapy or chemotherapy
- are carrying a pregnancy with fetal demise or vanishing twin
- have a history of organ transplant
- have mosaicism or maternal aneuploidy, which are rare maternal biological conditions
- have a maternal autoimmune disease
- have received a blood transfusion in the last 12 months
- have partial chromosome aneuploidy (a genetic disorder)
- have triploidy (a rare chromosomal abnormality)
The Warwick Evidence Systematic Review of the performance of NIPT found that the negative predictive value (NPV) of NIPT was 99.9%. The NPV tells you how likely it is that a low probability NIPT result is correct. This means that if you get a result that shows a low probability of the chromosomal conditions you can be fairly certain you do not have a fetus with any of the conditions.
The positive predictive value (PPV), which shows how likely it is that a high probably NIPT result is correct, varies for each condition tested:
- 82% for Down’s Syndrome (known as Trisomy 21)
- 49% for Patau’s Syndrome (known as Trisomy 13)
- 37% for Edwards' Syndrome (known as Trisomy 18)
A high probability result does not definitively confirm the presence of one of the conditions and further testing is required.
The NIPT test will detect 99% of pregnancies where a high probability of Down's Syndrome, Edward’s Syndrome or Patau’s Syndrome is present.
Results can also be inconclusive, which happens in less than 1% of cases. This is usually because the proportion of fetal DNA present in the sample is not high enough to give an accurate result. The test may be repeated with the hope that the fetal DNA levels will have increased due to the increased gestation. In some rare cases however, the fetal DNA is naturally low and in these instances a result cannot be yielded.
The NIPT is more accurate than the first trimester combined test or second trimester quadruple test for estimating the chance that the baby has Down's Syndrome. The combined false positive rates are 0.13% for Downs Syndrome, Edwards' Syndrome and 0.01% and Patau's Syndrome. Conventional screening tests can miss 15% or more of Down’s Syndrome pregnancies.
cfDNA is short for ‘circulating free DNA’. Fetal cfDNA is the circulating free DNA from your fetus in a maternal blood sample. The proportion of cfDNA in maternal blood that comes from the placenta is known as the fetal fraction.
The fetal fraction must be above 1.4%, which typically occurs around the tenth week of pregnancy. Low fetal fractions can mean the NIPT test can’t be done, or create a false negative result. Reasons for low fetal fractions include testing too early in the pregnancy, sampling errors, maternal obesity, and fetal abnormality.
An ultrasound Nuchal Translucency (NT) measurement (which measures the thickness of the fluid at the back of the baby's neck) when combined with a blood test and other maternal information provides an indication of the likelihood of a baby being born with Down’s Syndrome.
NIPT directly analyses the cell-free fetal DNA circulating in the pregnant mother's blood to detect the presence (or absence) of Down’s Syndrome, Edward’s Syndrome and Patau’s Syndrome.
The detection rate for NIPT is among the highest available for this type of antenatal screening and is recommended by the International Society of Prenatal Diagnosis (ISPD).
Yes, but not for triplets or higher multiple pregnancies. If one of the fetuses is no longer viable, the Harmony NIPT test cannot be performed.
We’ll take a new sample at no extra cost. There is a 0.2% failure rate for the overall test.
On rare occasions, NIPT is unable to provide an assessment of the probability of specific chromosome disorders. This usually reflects the complex biology of genetics and pregnancy, and is not due to a failing in the laboratory.
If NIPT cannot provide a specific assessment, it is not worth repeating the NIPT (unless advised by the laboratory). A decision about other tests (maternal serum screening, detailed ultrasound, amniocentesis or CVS) should be based on the doctor’s assessment of all risk factors identified, and may require specialist consultation with your doctor.
Yes, because with increasing body weight there is an increasing probability that there will be insufficient cell-free fetal DNA to provide a reliable result. On average, women who weigh 140kg will have a fetal fraction rate that is approximately half that of a woman weighing 70kg. This may increase the chance of getting an inconclusive result.
No, we do not offer this. A microdeletion is the absence of a small piece of chromosome and is named by the area of the chromosome that is absent. Due to a lack of research into the reliability of this test, we do not offer it.
This test has a 0.13% false positive rate. Results should always be confirmed by amniocentesis or Chorionic Villus Sampling (CVS) before making any decisions regarding subsequent management of your pregnancy. We always recommend you discuss your results with your Midwife or Consultant.
We do not offer this type of screening to evaluate the X and Y chromosomes. This is due to a lack of research currently available into the accuracy and detection rates of this test.
Absolutely! Every scan at Ultrasound Direct is performed by a fully qualified sonographer whose primary interest is your health. All our sonographers are fully trained and appropriately qualified to perform ultrasound scans. Many of our team also work in the NHS locally.
We are also registered with the Care Quality Commission, an independent regulator, to make sure you always receive the highest possible standards of care.
All our sonographers who take blood for blood tests are phlebotomy trained.
If you are experiencing pain or bleeding, go directly to your local A&E or contact your midwife – do not book an ultrasound scan. This is because you may be experiencing a medical emergency and waiting for a scan will cause a potentially harmful delay.
Research suggests that there are no known risks to our method of ultrasound scanning. Scans are painless (although an internal scan may be slightly uncomfortable) and have no known side effects. Ultrasound scans do not use any form of ionising radiation, unlike other diagnostic imaging services such as x-rays.
During pregnancy scans, we can record your baby’s pulsebeat – this sounds very similar to the heartbeat, but is recorded in a different way. We record the pulsebeat by scanning blood flow through the umbilical cord, rather than recording the heartbeat by scanning the heart. This is because consistent ultrasound output in one place can have a heating effect, and we don’t want to put your baby at any level of risk. The fast-moving blood in the umbilical cord quickly disperses any potential heating effect.
Information about NIPT with twins
You can have the NIPT test if you are carrying twins. There are a few restrctions:
- you cannot have the NIPT if one twin has passed away
- you cannot have the NIPT if an empty second sac is seen
- you can have the NIPT if your pregnancy is a result of IVF when two embryos are transferred and one is viable
If you have a high probability result for male twins, the results apply to one or both boys. If you have a high probability for female twins, the results apply to both girls.
What you get with Ultrasound Direct
Preparing for your scan
bring any medical notes you have, either printed or on your phone
drink one litre of clear fluid about one hour before your NIPT appointment
don’t urinate before your appointment. This is to give us the best view of baby
we’ll need access to your abdomen, so please wear a two-piece outfit (like a top and trousers, or a top and a skirt)
Here are some more places you can find useful information about NIPT: