The UK National Screening Committee advises pregnant women to attend a non-invasive screening test (NIPT) to detect the presence of Down Syndrome, and pleads for it to be accessible in hospitals.
The non-invasive test should be rolled out across the country so that mothers, regardless of wealth, can have equal access to screening and do not have to face the unnecessary risk of miscarriage Labour MP Tulip Siddiq in the Daily Mail UK (15/01/2016)
Indeed, experts are now recommending that instead of the amniocentesis test, women be offered a Non-Invasive Prenatal Test (NIPT).
What is a NIPT?
It is a blood screening test, performed on a standard blood draw taken from the mother-to-be, which picks up cell-free fragments of the baby’s DNA circulating in the mother’s bloodstream. NIPT’s are able to detect Down Syndrome (trisomy 21) and other trisomies like Patau and Edward Syndrome, Sexual chromosome abnormalities and chromosome microdeletions.
From which gestational week NIPT is most accurate?
During pregnancy, cell free fragments of the baby’s DNA circulate in the mother’s blood. Cell-free DNA is detectable from the 4th week of gestation and its concentration increases during the following weeks. The amount of fetal DNA present in the mother’s bloodstream from the 10th week of gestation is sufficient to perform the test with a very high level of accuracy of the results.
NIPTs avoid unnecessary amniocentesis
Currently, all pregnant women in the UK are offered a combined blood and ultrasound test when they are ten to fourteen weeks pregnant, to check for genetically associated anomalies of the foetus. Most of the European countries have in place a similar standard procedure for prenatal screening.
Under present guidelines women whose test shows an increased chance of giving birth to a baby with Down Syndrome are then to go ahead and perform an invasive diagnostic procedure such as amniocentesis or chorionic villi sampling, in which a long needle takes a sample of the amniotic fluid or placenta respectively.
In most of European countries women from 35 years old are advised for amniocentesis, regardless of combined blood and ultrasound test result.
Only 65% of women in the UK agree to take the current invasive amniocentesis test due to the risk of triggering miscarriage.
Countries recommendations in general are still to verify the NIPT result with an invasive procedure, but negative results can prevent thousands of unnecessary amniocentesis each year.
Therefore, the UK Government has recommended that all pregnant women be offered the chance to undergo this non-invasive screening test.
Screening during pregnancy can be an anxious time for the parents. Non-Invasive Prenatal Test represents an important and effective improvement over traditional methods.
For more informations about NIPT performances and screened disorders, visit Genoma’s page about
Tranquility: the prenatal test for trisomy 21, 18 and 13 which also identifies sex chromosomal abnormalities, microdeletions and the sex of the baby.