NT Scan & Dual Marker Test in Delhi
The 11–13 week screening scan that estimates the chance of Down syndrome and two other chromosomal conditions.
What NT scan & dual marker test involves
The nuchal translucency scan measures the fluid layer at the back of the baby's neck and checks the nasal bone and blood flow through the heart and liver. Combined with a blood test for PAPP-A and free beta hCG, and adjusted for your age, it produces a numerical risk for trisomy 21, 18 and 13.
It is a screening test, not a diagnosis. It sorts pregnancies into higher and lower risk so that the small number who need a diagnostic test — NIPT, or amniocentesis — can be identified. The window is narrow: it must be done between 11 weeks 0 days and 13 weeks 6 days, and it cannot be repeated later.
Who this is for
- All pregnancies, as the standard first-trimester screen
- Maternal age above 35
- Previous pregnancy affected by a chromosomal condition
- Anxiety about chromosomal risk, where a number helps more than reassurance
Not everything on this list means you need this treatment. The workup comes first, and the recommendation follows from what it shows — not from what was booked before you arrived.
Step by step
Timing
Booked between 11 and 13+6 weeks, ideally around 12 weeks when the measurement is most reliable.
The scan
Nuchal translucency thickness, nasal bone, ductus venosus flow and tricuspid regurgitation, plus a first structural survey.
The blood test
PAPP-A and free beta hCG, ideally drawn a few days before the scan.
The combined risk
Software combines scan, bloods and maternal age into a single risk figure, which we explain in full.
Your results, in writing
Whatever the outcome of NT scan & dual marker test, you leave each stage with the findings written down — what was done, what was found, what it means, and what the options are from here. Reports are issued the same day wherever the laboratory allows it.
Case study: A raised NT that was not what it first appeared
36, Green Park · NT scan at 12+3 · first pregnancy
What she came in with
A routine first-trimester screening scan in a pregnancy conceived naturally, with no family history of concern.
What the workup showed
Nuchal translucency measured 3.6 mm — above the normal range. The nasal bone was present and ductus venosus flow was normal, but the combined risk with her age and biochemistry came out at 1 in 90 for trisomy 21.
What we did
The number was explained properly: a 1 in 90 risk means an 89 in 90 chance the baby is unaffected. NIPT and chorionic villus sampling were both offered with their accuracy and risks set out, with no steer. She chose NIPT, which was low risk for all three trisomies. A detailed fetal echocardiogram was arranged at 20 weeks, because a raised NT is also associated with cardiac anomalies independent of chromosomes.
Outcome
The fetal echo and anomaly scan were both normal. A healthy baby was delivered at term.
The point of this case
A raised NT is not a diagnosis, and most babies with one are normal. But it earns a fetal echo even after a normal chromosomal result, which is the step most often skipped.
Illustrative case. This is a composite of presentations commonly seen in this practice, written for explanation — it is not the record of an identifiable patient, and no individual's details are used. Outcomes vary, and nothing here is a prediction of what will happen in your case.
What is different about having this done here
Scan performed by your own consultant, not a separate sonologist
The number explained properly — what 1 in 400 actually means for you
NIPT and amniocentesis discussed without pressure in either direction
Early structural look included, which sometimes picks up major anomalies at 12 weeks
Treated by the consultant, not by a rotating team
Dr. Tiwari performs the scans, the procedure and the follow-up herself, and looks after any pregnancy that results. Over a long treatment course that continuity is the difference between being known and being processed.
- MBBS, MS (Obstetrics & Gynaecology), FNB (Reproductive Medicine)
- Over ten years in reproductive medicine and gynaecological surgery
- Consultations and scans at Mother's Hope, Katwaria Sarai; theatre work at SHE Delhi Hospital, Greater Kailash II
- Itemised costs given in writing before anything begins
Areas we see patients from
Both locations are in South Delhi. Patients travelling from further out have appointments grouped to cut down the number of trips.
Questions about NT scan & dual marker test
What is a normal NT measurement?
Generally under 3.0 mm, though it varies with crown-rump length. A raised NT is not a diagnosis — most babies with a thick nuchal translucency are entirely normal — but it does prompt further testing and a detailed fetal heart scan.
Should I have NIPT instead?
NIPT is considerably more accurate for trisomy 21 but costs more and does not replace the scan, which also looks at structure. A common approach is the NT scan first, with NIPT if the risk comes back intermediate or high.
What if I miss the window?
After 14 weeks the nuchal translucency can no longer be measured. The alternatives are NIPT, or the quadruple marker blood test at 15–20 weeks, which is less accurate.
Talk it through before you commit
Consultations run for a full hour. Bring any previous reports — they are reviewed properly, not repeated.