"With just one sample of the mother's blood, can we find out early whether a foetus is at risk of a chromosomal abnormality?"
In the early weeks of pregnancy, alongside ultrasound and routine tests, NIPT is one of the prenatal screening tests that many expectant mothers ask about.
NIPT can be carried out from the 10th week of pregnancy, and it has high sensitivity and specificity for certain common chromosomal abnormalities. However, it is not a mandatory test and it is also not a diagnostic test.
So what is NIPT, is it necessary, and when is the most suitable time to have it?
What Is NIPT?
🧬 NIPT stands for Non-Invasive Prenatal Testing – non-invasive prenatal screening.
During pregnancy, the mother's blood contains fragments of free DNA (cell-free DNA – cfDNA), some of which originates from the placenta and reflects genetic information relating to the foetus.
By taking a sample of the mother's blood and analysing the cfDNA, NIPT helps to estimate the risk of the foetus having certain abnormalities in chromosome number without any direct intervention in the amniotic cavity.
According to the Ministry of Health's 2026 reproductive health care guidance, cfDNA/NIPT testing is a screening method with high sensitivity and specificity for Trisomy 21, Trisomy 18 and Trisomy 13.
Which Abnormalities Can NIPT Screen For?
NIPT packages differ in the range they analyse, depending on the technology and the testing facility. The abnormalities most commonly screened for include:
🔹 Trisomy 21 – Down syndrome
This occurs when the foetus has an extra copy of chromosome 21.
🔹 Trisomy 18 – Edwards syndrome
It may be linked to a number of serious abnormalities of development and of the organs.
🔹 Trisomy 13 – Patau syndrome
It may cause serious abnormalities of the brain, the heart and many other organs.
Some expanded NIPT tests also screen for sex chromosome abnormalities or certain other genetic changes.
However, a wider testing range does not mean that every abnormality is detected with the same accuracy. SMFM does not currently recommend the routine use of NIPT to screen for all microdeletion syndromes in the general population.
Is NIPT 99% Accurate?
This is one of the points that is most easily misunderstood.
NIPT is regarded as one of the screening methods with the highest sensitivity and specificity for the common trisomies, particularly Trisomy 21. However, it should not be taken to mean that:
👉 NIPT is more than 99% accurate for every condition.
👉 A high-risk result means the foetus certainly has the condition.
👉 A low-risk result means the foetus has no genetic abnormality at all.
According to SMFM, cfDNA/NIPT is currently the screening test with the highest sensitivity and specificity for Trisomy 21, 18 and 13, but there remains the possibility of a false positive or a false negative.
That is why NIPT is called a screening test, not a diagnostic test.
Does A High-Risk NIPT Result Mean The Foetus Definitely Has An Abnormality?
❌ No.
A high-risk NIPT result means the foetus has a higher likelihood of having the abnormality being screened for, but it is not enough to make a final diagnosis.
Your doctor may advise further diagnostic methods such as:
📋 Chorionic villus sampling (CVS)
📋 Amniocentesis
📋 Specialist ultrasound
📋 Genetic counselling
SMFM recommends that abnormal cfDNA results should be confirmed with a diagnostic test before any important decisions about the pregnancy are made.
Is NIPT Mandatory?
No. NIPT is not a test that every expectant mother is required to have.
Prenatal genetic screening and diagnosis should be based on medical advice, the state of the pregnancy and the choice of the pregnant woman herself.
Both ACOG and SMFM stress that pregnant women have the right to choose to have or to decline genetic screening and diagnostic testing once they have been given full information.
The 2026 guidance from the Vietnamese Ministry of Health also lists NIPT as one of the prenatal screening options, which may be used from the outset or as the next step in certain cases.
The more useful question, then, is not:
“Is NIPT mandatory?”
but rather:
“For my pregnancy, is NIPT the right screening option?”
Who Should Consider Having NIPT?
NIPT is no longer intended only for pregnant women aged 35 and over.
SMFM's updated recommendation is that cfDNA should be offered as an option for screening for the common trisomies to all pregnant women, regardless of maternal age or baseline risk, once they have received appropriate counselling.
NIPT may be particularly worth considering in the following cases:
✔️ The mother wants early screening for the risk of chromosomal abnormality
✔️ The mother is pregnant at the age of 35 or over
✔️ An earlier screening result showed a risk of chromosomal abnormality
✔️ There is a history of a previous pregnancy or child with a chromosomal abnormality
✔️ There are risk factors that need to be assessed by an obstetrician or a genetics specialist
✔️ The mother would like a high-performing screening method that does not involve intervention in the amniotic cavity
In cases where ultrasound has detected a structural abnormality in the foetus, simply adding NIPT is not necessarily the best option. Your doctor may advise diagnostic testing or specialist assessment, depending on the situation.
From Which Week Should NIPT Be Done?
⏰ NIPT can be carried out from the 10th week of pregnancy.
This is also the point set out in the reproductive health care guidance of the Vietnamese Ministry of Health in 2026 for cfDNA testing.
Why wait until week 10?
NIPT needs enough placenta-derived cfDNA in the mother's blood for the analysis to be carried out.
If the test is done too early, the proportion of cfDNA may not yet be sufficient, which increases the chance of:
🔹 No result being obtained
🔹 Needing a repeat blood sample
🔹 Having to undergo further tests
SMFM also notes that testing too early is one of the possible causes of a NIPT result being “non-reportable” – meaning no clear result can be given.
Is Week 10 The Only Time NIPT Can Be Done?
No.
Week 10 is the point from which the test can begin, not the only week in which it can be done.
Expectant mothers at later weeks of pregnancy may still be advised by their doctor to have NIPT if it is suitable.
Screening early does, however, have one important advantage: if the result needs further assessment, the mother and her doctor will have more time for genetic counselling, ultrasound or follow-up diagnostic testing.
Is An Ultrasound Needed Before NIPT?
🔎 It is valuable and strongly advised as part of routine pregnancy care.
The Ministry of Health's 2026 guidance states that in the first trimester, pregnant women should have at least one ultrasound before cfDNA testing in order to establish:
✔️ Gestational age
✔️ The number of foetuses
✔️ Foetal viability
At the same time, NIPT does not replace foetal ultrasound.
The Ministry of Health still recommends a detailed morphology ultrasound in the second trimester, ideally at around 18–22 weeks, to detect structural abnormalities in the foetus.
Does NIPT Replace The Double Test?
According to the Ministry of Health's 2026 guidance, NIPT may be used:
👉 As the main screening method from the outset.
Or
👉 As a second-step screening test when a traditional biochemical test returns a high-risk result.
The Double Test/Triple Test still has a role in facilities where cfDNA is not yet available, or when pregnant women do not wish to have NIPT or are not yet in a position to do so.
Not every expectant mother therefore has to go through the sequence Double Test → NIPT.
The choice of screening strategy should be agreed with your doctor on the basis of gestational age, ultrasound findings and the characteristics of each pregnancy.
Does NIPT Replace Amniocentesis?
❌ No.
The two tests serve different purposes.
NIPT: screening for risk.
Amniocentesis: may be used to obtain a sample for diagnostic genetic testing.
A major advantage of NIPT is that it needs only a sample of the mother's blood, so it carries none of the procedural risk involved in passing a needle into the amniotic cavity.
However, if NIPT returns a high-risk result or the foetus shows signs of a notable abnormality, your doctor may still recommend a diagnostic test such as amniocentesis or chorionic villus sampling.
If The NIPT Result Is Low Risk, Is A Foetal Ultrasound Still Needed?
✅ Yes, it is.
This is something expectant mothers very easily overlook.
NIPT screens only for certain specific genetic abnormalities and cannot detect every birth defect or developmental problem in the foetus.
Even when NIPT returns a low-risk result, therefore, the mother still needs:
📋 Regular antenatal check-ups
📋 Ultrasound at the key stages of pregnancy
📋 Foetal morphology ultrasound
📋 Any other tests as directed by her doctor
A low-risk NIPT result means that the risk of the abnormalities tested for is substantially reduced, not that the foetus is certain to have no health problems at all.
Is NIPT Safe For Mother And Foetus?
NIPT is described as non-invasive because the test sample is taken from the mother's peripheral blood.
Unlike amniocentesis or chorionic villus sampling, taking a sample for NIPT does not require any instrument to be passed into the womb or the amniotic cavity.
The test therefore carries no risk of miscarriage from an invasive procedure to sample the foetus.
That said, describing NIPT as “absolutely safe” is not really necessary. As with any blood draw, the person being tested may still experience mild discomfort, bruising or brief light-headedness at the time the sample is taken.
3 Things Expectant Mothers Should Remember Before Having NIPT
🧬 1. NIPT is screening, not diagnosis
A high-risk result needs to be assessed by a doctor and may require a diagnostic test to confirm it.
⏰ 2. It can be carried out from the 10th week of pregnancy
Testing too early is not advisable, as there may not yet be enough cfDNA to analyse.
🩺 3. NIPT does not replace antenatal check-ups and ultrasound
A low-risk NIPT result cannot rule out every foetal abnormality.
Where Should NIPT Be Done?
When choosing a facility for NIPT, expectant mothers should not compare them only on “how many conditions the test covers”.
Some factors that matter more include:
✔️ The laboratory and the technology it uses
✔️ The range of abnormalities screened for
✔️ The availability of counselling before and after the test
✔️ The procedure followed if the result is high risk or no result can be given
✔️ The ability to connect you with an obstetrician and a genetics specialist when needed
With expanded NIPT packages that screen for a great many rare syndromes in particular, mothers should discuss in detail the real value and the limitations of each item, rather than assuming that the more indicators a package covers, the better it is.
With Halza, Mothers Can Take More Control Of Their Pregnancy Journey
📱 On Halza, mothers can:
✔️ Search for hospitals and medical facilities offering pregnancy care services
✔️ Book appointments and tests conveniently
✔️ Store NIPT results, ultrasound scans and pregnancy records on a single platform
✔️ Track health records throughout the pregnancy
✔️ Manage health information for both mother and family
A test may take no more than a single blood draw, but what matters more is understanding the result correctly and knowing what the next step should be.
References
📚 Vietnamese Ministry of Health – Reproductive health care guidance, 2026
📚 Society for Maternal-Fetal Medicine (SMFM) – Consult Series #74: Cell-free DNA screening for aneuploidies, 2025
📚 American College of Obstetricians and Gynecologists (ACOG) – Screening for Chromosomal Abnormalities
📚 National Health Service (NHS) – Screening tests in pregnancy
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