NIPT (Non-Invasive Prenatal Screening) Blood Tests
Pregnancy is a time filled with excitement and anticipation of a new addition to the family. It can also be a time that raises many questions and concerns regarding the health of your baby.
Most frequent questions and answers
NIPT is a term used in antenatal screening, it looks at DNA in the chromosomes that originate from a baby’s placenta and with today’s technology, it can be found in a sample of a mother’s blood. It is used to identify 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.
Aneuploidy is a genetic condition where a person has an abnormal number of chromosomes either because the chromosomes are missing or are additional. Sex/gender chromosome aneuploidies have either missing or extra copies of the X or Y chromosomes, such as Turner’s Syndrome and Klinefelter Syndrome.
Trisomy is a genetic condition where an abnormality occurs where one of the 46 pairs of chromosomes contains 3 chromosomes instead of two as with Trisomy 21 (Downs Syndrome).
NIPT Screening tests cannot, determine for sure whether your baby actually has a chromosomal disorder, only predict the likelihood of having that condition. But – even though it can’t tell for sure whether your baby has a genetic abnormality, it is highly accurate — 97 to 99 percent accuracy for three of the most common conditions, according to research from 2016.
- A singleton pregnancy
- And twin pregnancies (including vanishing twin)
- Pregnancies achieved by IVF techniques, including gamets donation
NIPT involves a quick blood sample, making it quick and easy for you and your baby. Your sample is then sent to a lab, where a technician will look at the DNA in your blood for signs of abnormalities.
Once the results of your NIPT are analysed the laboratory will determine whether you are placed in the LOW or HIGH risk category. This will indicate whether diagnostic testing is needed to confirm the result.
Trimester ONE NIPT test is available from 9 week’s gestation. All other NIPT’s can be performed any time after 10 weeks — these are earlier than any other antenatal screening or diagnostic test.
Whilst other forms of NHS screening;
- Nuchal translucency scanning is done between weeks 11 and 13
- CVS is done at 10 to 13 weeks
- Quad screen between weeks 14 and 22
- Amniocentesis is usually performed between weeks 16 and 18, but it’s sometimes done as early as week 13 or 14 and as late as week 23 or 24.
Research suggests that NIPT tests create less false alarms than standard NHS first-trimester blood screenings (like first-trimester bloodwork or quad screening) that measure hormones and special proteins in a mother’s blood.
Research has shown that NIPTs are more accurate than those same standard screenings in predicting the risk of Down syndrome
Many of the women referred to us are from our NHS colleagues following high risk reported results from combined testing.
Many parents wish to plan ahead and choose to find out the gender of their baby. This can be chosen with any of our NIPT tests ( please see T & C’s)
In the event of a high risk NIPT result we make a medical referal to the clients local fetal medicine unit to help them decide 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, between 1-3% nationally.