Non-Invasive Prenatal Test

It has been discovered that a blood sample taken from the mother from 10 weeks of pregnancy onwards can be analysed for cell free fetal DNA (cfDNA), which represents a sample of the fetal-placental DNA, derived from placental trophoblasts, in the mother’s blood.

This prenatal screening method involves taking a safe blood sample from the mother’s arm. There is no increased miscarriage risk to your baby from having this simple, safe maternal blood test. The cell free fetal DNA (cfDNA) which is present in the mother’s blood is then analysed, the results determine if there is a high probability or low probability of the baby having one of the three screened conditions; Down’s syndrome, Edwards’ syndrome and Patau’s syndrome. These conditions are also known as Trisomy 21, Trisomy 18 and Trisomy 13. 

NIPT can be used in twin, singleton donor and surrogate pregnancies. You can also choose to find out the sex of your baby by looking at baby’s chromosomes, this is optionally included in your NIPT. In some circumstances it may not be possible for the NIPT to report on the sex of your baby, such as Vanishing twin pregnancies.

If you have had any complications in your current pregnancy such as a vanishing twin. We would request that your most recent ultrasound report is sent to us ahead of your appointment. 

Non-invasive prenatal testing is available from several different laboratories across Europe, China and the U.S.A. The Harmony NIPT is processed and analysed for The Birth Company by The Doctors Laboratory ( TDL) in London. The Panorama NIPT is processed and analysed for The Birth Company by Natera inc. in the USA. The SAFE Test NIPT is processed and analysed for The Birth Company by St Georges University Hospital in London.

There are other NIPT providers available including Neobona, Maternit21, Verifi and Serenity. The laboratories process and analyse cfDNA, however they use slightly different methods of analysis.

Parents to be who wish to find out the likelihood that their baby has one of three chromosomal conditions; Down’s syndrome (T21), Edward’ syndrome (T18) or Patau's syndrome (T13) choose NIPT. This prenatal test can be performed two weeks earlier than the NHS 11-14 week Nuchal Translucency screening.

Tiny structures inside your baby’s cells called chromosomes carry the genes that determine how your baby develops. There are 23 pairs of chromosomes per cell, however changes may occur during the production of sperm or egg cells which can lead to your baby having an extra chromosome. Although babies with Trisomy 21, Trisomy 18 and Trisomy 13 are born to mothers of all ages, maternal age increases the likelihood of the presence of these conditions. NIPT analyses the cffDNA in the maternal blood, to determine if there is an increased likelihood that your baby has an extra chromosome present. Downs Syndrome, Edwards Syndrome and Pataus Syndrome are spectrum conditions varying from mild to severe presentation.

The Nuchal Translucency screening offered by the NHS determines a background chance based on maternal age. From the maternal age of 35 years of age onwards this background chance increases substantially. This increases the likelihood of receiving a high probability result from the Nuchal Translucency screening. Due to the limitation of the Nuchal translucency screening, this lowers the positive predictive value (PPV) of the test, meaning that those over 35 are more likely to receive a high probability result, even if the baby does not have the condition.

NIPT has a higher positive predictive value than the Nuchal translucency screening. This means less high probability results where the condition is not actually present. We do not use the term false positives, as these are screening tests therefore, they do not determine positives or negatives. They offer likelihoods, from low to high.

NIPT is particularly recommended for those over 35 years of age, parents to be who have had a high probability result in their current or previous pregnancy, or a confirmed chromosomal condition in a previous pregnancy. It is for those who wish to avoid unnecessary invasive testing, which carries a risk of miscarriage.

The most preferred NIPT is the Harmony Test. If you know which NIPT you wish to have please read the consent form prior to your appointment:

Harmony Test Consent Form 

Panorama Test Consent Form Aneuploidy

Panorama Test Consent Form 22Q

SAFE Test Consent Form

If you are undecided which NIPT you wish to have our Specialist Sonographers will be happy to discuss this during your appointment.

• An ultrasound scan is always performed prior to the NIPT blood test. This ensures that your baby is healthy, with a strong heartbeat and growing well. This scan will also confirm if it is a singleton or multiple pregnancy. Our specialist sonographer will check that baby is developing well and confirm your estimated due date, or EDD. Your baby must measure over 10 weeks gestation for the NIPT performed, therefore it may be best to wait until a few days past 10 weeks of pregnancy to visit us for your appointment to ensure your baby is developed enough.
• Our Specialist Sonographer will discuss the pros and cons of the three Non invasive prenatal tests available; Harmony, Panorama or SAFE. Prenatal counselling is important help you choose the best test for baby and for you. 
• Once the pregnancy scan has been performed and your NIPT options discussed, a consent form will be given to you to read and sign. If you have any questions, our specialist sonographers are here to answer them.
• A simple blood test is then taken from the vein of the mother’s arm like any other blood test. There is no risk to your baby from having this blood test performed.
• The blood sample tubes are immediately packaged and dispatched to the laboratory for processing and analysis.
• NIPT screening results determine if you have a low or high probability for Downs syndrome, Edwards syndrome or Pataus syndrome. They can also tell you the sex of your baby.
• If you receive a high probability result our expert team will discuss pathways, including further investigations such as detailed ultrasound scans, invasive testing, counselling or referral to your Fetal Medicine Unit (FMU). This can also be discussed with our Consultant.

Please note We recommend using our pregnancy calculator, or contacting our Specialist admin team if you are unsure of the best time to attend for your NIPT. NIPT can be performed from 10 weeks of pregnancy. If you are too early for NIPT when you attend for your appointment, an additional charge of £120 will be required to cover the cost of the additional appointment and scan required. 

Please note in the circumstance that during your appointment an ultrasound scan is performed but we do not proceed to the NIPT, a fee will be taken for the price of the scan. This can vary between £125 - £245 depending on gestation. The additional amount will be refunded to you.

Please note in the instance of a repeat full test failure, the NIPT laboratory fees may be refunded. A fee for the appointment services provided will be retained.

• Results take from 3-14 calendar days depending on the day of week/time of day the sample is taken or if the lab need to perform further analysis on your blood sample. Results take an average number of 7 days.
• As soon as The Birth Company receives the laboratory results, we will call you to explain them before emailing you a copy to keep in your maternity notes. Our team are in the clinic from 8am to 8pm daily, and Saturdays and Sundays. The laboratory portals are checked throughout the day, but we do tend to receive most results in the late afternoon
• In rare circumstances the result can take longer than 14 days. We understand it can be a stressful time waiting for results and we will endeavour to communicate any delays to our patients as soon as we receive information from the laboratory.

• The NIPT report will determine whether you have a low probability or high probability for Down’s Syndrome, Edwards’ Syndrome or Patau’s Syndrome (Trisomy 21, Trisomy 18 or Trisomy 13). This can be particularly reassuring if you have received a high probability Nuchal translucency scan.
• If you receive low probability results, the likelihood of your baby having each of the conditions is less than 1 in 10’000. This means that we would expect less than one baby to be born out of ten thousand births with the condition Down’s syndrome, Edwards’ syndrome or Patau’s syndrome.
• If you receive a high probability result, this will specify which trisomy there is a high probability of your baby having. This does not confirm that your baby has this condition, as this is a screening test only. Please note that the positive predictive value (PPV) for NIPT varies between Downs syndrome, Edwards syndrome and Pataus Syndrome and with maternal age. The PPV for Downs syndrome varies from 1 in 2 babies confirmed to have the condition to 9 in 10 babies confirmed to have the condition, therefore prenatal counselling and further investigation is recommended. During pregnancy, the only method available to diagnose if the condition is present is invasive testing such as chorionic villus sampling (CVS) or amniocentesis. 
• Due to the nature of the test, there is a 5-6% chance of receiving No Result from your NIPT blood sample. This is not a low probability, nor high probability. In most cases it is suitable to offer a redraw of the sample free of charge, including an ultrasound scan. The chance of receiving a screening result on the second draw is 50%. No Result is increased by maternal weight greater than 85kg.
• If you have selected the option of finding out the sex of your baby, this will also be documented on the NIPT report.

What happens if my NIPT gives No Result?

There is an increased likelihood of test failure for IVF pregnancies, twin pregnancies, mothers using blood thinners and mothers weighing over 85kg. Test failures can cause parents unnecessary concern.

If possible we recommend waiting until 11 or 12 weeks (or later) to perform your NIPT, this will increase the percentage of fetal fraction available for the test and reduce the likelihood of receiving no result.

Prior to this advance in prenatal screening, doctors and screening midwives used the results of the Nuchal Translucency Scan to advise parents to be if they had a low or high probability of their baby having the conditions Downs syndrome, Edwards syndrome or Pataus syndrome. The Nuchal Translucency Scan is a method of screening offered by the NHS from 11 to 14 weeks of pregnancy and includes several factors to determine this probability, including maternal age, the nuchal translucency measurement at the back of the baby’s neck and the maternal blood biochemistry (free ß-hCG and PAPP-A). This method is also known as the combined test. The greater the maternal age, the greater the background chance of the presence of the condition.

Nuchal Translucency screening test, or combined test, has a sensitivity of 84%. Parents to be who receive a high chance result are offered counselling by their screening midwife. This does not confirm the presence of the chromosomal condition. A diagnostic invasive test such as chorion villous sampling (CVS) or amniocentesis can confirm the presence or absence of the conditions Down’s syndrome, Edwards’ syndrome and Patau’s syndrome. A needle is used to take a sample of the pregnancy, through the mother’s tummy to allow for the analysis of fetal DNA. These invasive tests report a risk of miscarriage to the pregnancy of 1:100.

Since Non invasive prenatal testing (NIPT) became available many parents to be chose this more accurate prenatal screening. For comparison, when screening for Down’s syndrome using the Nuchal Translucency scan, the detection rate is 84% and positive predictive value (PPV) is less than 15%, meaning the actual number of high probability pregnancies that are later confirmed to have the condition Downs syndrome is less than 1 in 6.

When screening for Down’s syndrome using the Non Invasive Prenatal Test, the detection rate is 99% and positive predictive value (PPV) varies from 48% to 99% from 18 years maternal age to 50 years maternal age. The greater the maternal age, the greater the NIPT positive predictive value (PPV). You can use the NIPT Positive Predictive Value calculator here to calculate your PPV for each condition here:

NIPT Predictive Value Calculator  

This means using NIPT, the actual number of high probability pregnancies confirmed to have the condition Down’s syndrome vary from 1 in 2 (50%) confirmed with the condition to 9 in 10 (90%) of babies confirmed with the condition, depending on maternal age and other factors such as the presence of structural conditions.

For Edwards Syndrome the NIPT positive predictive value (PPV) is 2 in 5, or 40% likelihood that the baby is confirmed to have the condition. For Pataus Syndrome the NIPT PPV is reported as 1 in 2, or 50% of babies confirmed to have the condition after a high probability NIPT.

The results of the safe, simple NIPT blood test has a higher detection rate which will hugely reduce the need for unnecessary invasive testing by CVS or amniocentesis. This is great news for parents to be.

It is important that an ultrasound scan is performed just before the blood test to confirm the pregnancy, and to check if there are twins or more. Our Specialist Sonographers will perform a detailed early fetal scan, early anatomy scan or anatomy scan depending how many weeks pregnancy you are when you visit us for your NIPT.

Yes. Structural conditions such as brain, face, stomach, kidney, bladder and limb conditions, as well as Spina Bifida. Poor growth and development will only be demonstrated on ultrasound scans, often not until the second and third trimester. We always perform a detailed ultrasound scan when you attend for an NIPT. After your NIPT if you would like further reassurance that your baby is developing and growing well, our specialist sonographers are trained to perform early anomaly scans from 16 weeks of pregnancy.

 

There are further chromosomal conditions that can be screened for using NIPT, if you require screening for these rare conditions, your NIPT appointment must include a telephone consultation with our Consultant Obstetrician. The cost of Consultant led NIPT with full panel microdeletion screening is £830. Please find details of these below:

Harmony Test further testing

The Harmony Test offers screening for the rare conditions: Monosomy X, also known as Turner’s syndrome and other Sex Chromosome Aneuploids.

The positive predictive value of these conditions is much lower than for T21, T18 and T13. The purpose of NIPT is to reduce anxiety in pregnancy and reduce the number of invasive tests performed unnecessarily. Screening for rare conditions may increase the number of invasive tests performed. There is not a structured pathway within the NHS screening programme to support the screening of Monosomy X and Sex Chromosome Aneuploids from NIPT.

There are concerns that there is not enough evidence to support including screening for these rare chromosomal conditions. 

Panorama Test further testing

The Panorama NIPT offers screening for further conditions called triploidy (which is included routinely), sex chromosome aneuploids and microdeletions. There are concerns that there is not enough evidence to support including screening for these chromosomal conditions. The positive predictive value of the test for these conditions is much lower than for T21, T18 and T13. Screening for rare conditions may increase the number of invasive tests performed unnecessarily. There is not a structured pathway within the NHS screening programme to support the screening of sex chromosome aneuploids and microdeletions. Microdeletion screening is not available for twin or donor egg pregnancies.

Please note Blood samples for Panorama Natera are collected before 2pm Monday - Friday. Panorama Samples taken on Saturday and Sunday will not be collected/shipped by the Panorama Natera organised medical samples courier until Monday afternoon.

The SAFE test is the only NIPT that can be used for vanishing twin pregnancies. The SAFE test is less accurate for the sex of your baby than Harmony and Panorama. If a vanishing/demised twin pregnancy is diagnosed at a previous scan we would request that ultrasound scan is sent to us ahead of your appointment. Many miscarriages of pregnancy are caused by chromosomal conditions, therefore there is a high probability that there was a chromosomal condition present in the twin that has sadly passed. There is an increased likelihood of receiving a high probability result when a demised twin is present. Some evidence suggests that performing Non-Invasive Prenatal Testing 8 weeks after the demise of the second twin may reduce the likelihood of a false positive result.

A high probability result does not confirm the presence of a chromosomal condition in the live twin, only invasive testing can prenatally confirm or exclude chromosomal conditions.

The SAFE Non-Invasive Prenatal Test is unable to offer sex determination for vanishing twin pregnancies.

If you are looking for a second opinion, please ensure that you provide us with your relevant ultrasound report ahead of your appointment to ensure that we can provide you with the best service.

Ultrasound reports should be sent to bookings@thebirthcompany.co.uk

There is the option of three different Non Invasive Prenatal Tests (NIPT) at The Birth Company; Harmony Test, Panorama Test and Safe Test, costing from £500 each. Harmony NIPT is the most preferred option by our patients. This is due to the samples being processed in London, meaning results are received on average within 7 days (Please note in some circumstances results can take longer).

Appointments after 5pm, weekend and bank holiday appointments incur a £50 surcharge. Included with every NIPT is prenatal screening counselling, a detailed ultrasound scan performed by one of our Specialist Sonographers, and comprehensive support for NIPT results.

NIPT appointments with our Consultant Dr Gibb incur an additional charge of £150. Please note Dr Gibb is available on Thursday afternoons.

If the NIPT is low probability then it is important that the person conducting the 12 week scan or 20 week pregnancy scan is aware of this. If the test is high probability, then you should return to The Birth Company or your NHS Fetal Medicine Unit for further counselling.

Pregnant women are offered two routine ultrasound scans during pregnancy within the NHS, this is called the Fetal Anomaly Screening Programme. 

Depending on how many weeks pregnant you are, we recommend you take the opportunity to have a 11 to 14 week pregnancy scan privately or with the NHS. The focus of the 11 - 14 week scan will change as you will already know if you have a low chance for Down’s syndrome, Edwards’ syndrome and Patau’s syndrome. The 11 to 14 week pregnancy scan will look at the development of your baby in detail, our Sonographers are highly trained to perform early fetal scans and early fetal anomaly scans. These specialist private pregnancy scans and NHS scans look for structural conditions (these may exist without the presence of a chromosomal condition).

The other routine pregnancy scan offered by the NHS is around 20 weeks of pregnancy called the Anomaly scan. The purpose of this ultrasound scan is to assess your baby’s physical development and to look for 11 rare conditions, including head/brain and heart conditions.

The 20 week anomaly scan is a very important ultrasound scan during pregnancy.

More information about Downs Syndrome can be found here:

Downs Syndrome Association

More information about Edwards' syndrome and Patau's syndrome can be found here:

Screening tests for you and your baby

Screening tests for you and your baby translated versions 

For more guidance with prenatal screening please contact Antenatal Results and Choices: