NT Scan in Ahmedabad: What I Check Between 11 and 13+6 Weeks

Outside this narrow window the NT measurement cannot be used for screening, so I time the appointment from your dating scan.

The nuchal translucency (NT) is a thin layer of fluid at the back of the baby's neck. I combine its thickness with your age, the baby's heart rate and a blood test. This gives you a personal chance figure for Down syndrome and for two other trisomies. At the same appointment I count the babies, check whether twins share a placenta and, by adding a few extra measurements, estimate your risk of pre-eclampsia.

Every measurement follows the internationally audited FMF protocol, and I explain the result to you before you leave - in Gujarati, Hindi or English, whichever you prefer.

NT Scan Full Form and Meaning: The Nuchal Translucency in Plain Words

NT is short for nuchal translucency: "nuchal" refers to the back of the neck, and "translucency" to the clear, fluid-filled space seen there on ultrasound. In the first trimester, every baby has a little normal fluid under the skin behind the neck, which shows up on the screen as a dark strip. By roughly 14 weeks it usually disappears, and that is why the timing of this scan is so strict.

When this layer is thicker than expected, the chance of some conditions goes up. These include chromosomal conditions such as Down syndrome, some heart conditions, certain genetic syndromes and problems with the lymphatic system. I always stress that the NT tells us about chance; it does not make a diagnosis. Most babies whose NT is just slightly thick turn out to be healthy.

NT Scan Sonography: What I Look at on the Screen

• Crown–rump length (CRL) - this confirms your due date, or corrects it.
• Nuchal translucency - measured by the FMF method with the baby lying in a neutral position and the image enlarged; I record it in millimetres to one decimal place.
• Heartbeat - the heart rate, and how many babies there are.
• Chorionicity in twins - whether there are one or two placentas; this is judged most accurately before 14 weeks.
• Early anatomy - the skull and brain, face, spine, abdominal wall, stomach, bladder and limbs, and views of the heart where the baby's position allows.
• Extra markers, when they add useful information - the nasal bone, blood flow across the tricuspid valve, and flow in the ductus venosus.
• Pre-eclampsia screening - uterine artery Doppler together with your blood pressure.

A careful scan at 11–14 weeks can raise a suspicion of roughly 40–50% of major structural conditions. Even so, you will still need the detailed anomaly scan at 18–22 weeks.

NT NB Scan: Why I Check the Nasal Bone Too

You may see "NT NB scan" written on a referral slip or a report. It is not a separate test: NB stands for nasal bone, and it is checked at the same 11–13+6 week appointment as the nuchal translucency.

At this stage of pregnancy the small bone at the bridge of the baby's nose usually shows up as a bright line when the baby is seen exactly side-on. In babies with Down syndrome it is more often not yet visible. That makes it a useful extra marker - but only as one input. A nasal bone that cannot be seen does not mean the baby has a chromosomal condition. Many healthy babies simply show it a little later, and the result also depends on the baby's position.

So I never read the nasal bone on its own. It goes into the calculation alongside the NT, your age, the blood test and, where helpful, the flow across the tricuspid valve and in the ductus venosus. Used this way, the extra markers tend to sharpen the final figure and reduce false alarms, as the table further down shows. If the view is unclear, I try again after a short walk rather than guess.

NT Scan and Double Marker Test: How Your Screening Figure Is Worked Out

Six inputs go into the calculation: the NT, your age, the CRL, the baby's heart rate, free beta-hCG and PAPP-A. The FMF algorithm then produces a separate chance for trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome) and trisomy 13 (Patau syndrome). Each is written as a figure such as 1 in 8,000 or 1 in 60.

Most centres call a result "higher chance" when it is above a cut-off of about 1 in 100 to 1 in 150. Results falling between about 1 in 100 and 1 in 1,000 are sometimes described as intermediate, and for these NIPT is a reasonable next step. Your weight, ethnicity, smoking, diabetes and conception by IVF all change how the hormone values are read, so please make sure the details on your form are correct.

How well different approaches pick up Down syndrome (approximate figures from published data):

Checking Pre-eclampsia Risk at the NT Visit

Pre-eclampsia is common in India and can be serious. Its early form, which needs delivery before 34 weeks, carries the greatest risk for mother and baby. I estimate your risk from your history, blood pressure taken in both arms, uterine artery Doppler, and PAPP-A (or PlGF where that test is available).

If your risk works out at 1 in 100 or higher, I usually advise low-dose aspirin, typically 150 mg at night. It is started before 16 weeks and continued up to 36 weeks. In the large ASPRE trial, this approach cut preterm pre-eclampsia by about 60%. Whatever the chromosomal result, this is a part of the visit I consider clinically important.

When the NT Result Comes Back Higher Chance

A higher-chance result means we should sit down and talk it through. To put a number in context: with a result of 1 in 50, forty-nine out of fifty women in the same position have a baby without the condition.

The choices I go through with you are:

• NIPT, a blood test
• Chorionic villus sampling (CVS), possible from 11 weeks.
• Amniocentesis, possible from 15 weeks.
• Deciding not to test further.

When the NT is 3.5 mm or more (above the 99th centile), I usually discuss going straight to diagnostic testing with chromosomal microarray. I prefer this to NIPT here, because NIPT does not look for smaller chromosomal changes or for some genetic syndromes. An early heart scan (fetal echo) around 16 weeks and a detailed anomaly scan come next. If the chromosomes and the later scans are normal, most of these babies are born healthy.

What an NT Scan Cannot Tell You

• Like every screening test, it gives some false-positive and some false-negative results.
• Roughly 1 in 10 babies with Down syndrome falls into the low-chance group.
• Some structural conditions develop later in pregnancy or are too small to see at 12 weeks.
• Sometimes I cannot get the measurement because of the baby's position, your body build or a retroverted (tilted) uterus. A short walk, a second attempt or a vaginal scan usually solves this; if it still cannot be measured, I discuss other screening options with you.

Twins and IVF: How the NT Scan Differs

In twins, I measure an NT for each baby and calculate each baby's chance separately. Finding out at this scan whether the twins share a placenta matters a great deal. Monochorionic twins (sharing one placenta) are scanned every two weeks from 16 weeks, so that twin-to-twin transfusion syndrome can be recognised early.

After IVF or ICSI, I take the due date from the embryo transfer date rather than from the CRL. Hormone levels can run slightly differently in IVF pregnancies; the algorithm adjusts for this, which is why the method of conception goes on the form.

NT Scan in Pregnancy: In Which Week Should It Be Done?

The NT scan in pregnancy is done between 11 weeks 0 days and 13 weeks 6 days - in months, roughly the end of the third month. Within that window I usually aim for 12–13 weeks.

The limits come from the baby's size rather than the calendar. The screening calculation is only valid when the crown–rump length is 45–84 mm. Below that, the baby is too small for the early anatomy check. After about 14 weeks, the fluid behind the neck is absorbed as the baby's lymphatic system matures. The measurement then no longer carries the same meaning.

Counting from your last period works when your cycles are regular and you are sure of the date. If they are irregular, or you conceived soon after stopping the pill or while breastfeeding, an early dating scan gives a firmer date to plan from. After IVF, the transfer date is used. A practical rule: call for an appointment at about 10 weeks. A convenient slot is then still available inside the window, and the blood sample can be timed with it.

How I Organise Your NT Appointment

• I book the NT scan as a full consultation so that there is time to measure carefully and to explain the result.
• I take the NT measurement myself, following the FMF protocol for which I hold accreditation.
• Once the blood values are in, the combined risk is calculated - usually on the same day.
• Please bring your dating scan report, any earlier pregnancy records, a list of your medicines and, if they apply to you, your latest diabetes or thyroid results.
• Your husband or a family member is welcome to come in with you; we can talk in Gujarati, Hindi or English.
• If the result is low chance, we plan your next visit around the 18–22 week anomaly scan.
• If the result is higher chance, or your pre-eclampsia risk is raised, the counselling visit or the aspirin plan is arranged before you leave.

Your NT Visit from Booking to Report

1. Choosing the weekI time the booking from your dating scan so that the baby measures 45–84 mm; around 12–13 weeks is ideal.
2. Blood samplefree beta-hCG and PAPP-A are taken on the day, or a few days earlier; your weight, history and medicines are noted.
3. The scan itselfthe NT, early anatomy and Dopplers are checked, usually through the abdomen; occasionally a short vaginal scan is needed.
4. Your resultI explain the trisomy and pre-eclampsia chances at the same visit and give you a written report.
5. What comes nextbefore you leave we agree on the next step: aspirin, NIPT, counselling, an early heart scan, or the anomaly scan at 18–22 weeks.

Who Should Plan an NT Scan

Please book an appointment in any of these situations:

• You are between 11 weeks and 13 weeks 6 days, or will be soon.
• You are 35 or older, or conceived through IVF or ICSI.
• A previous baby had a chromosomal, genetic or structural condition.
• You are expecting twins and the number of placentas needs to be confirmed.
• You have had pre-eclampsia before, or have high blood pressure, diabetes, kidney disease or APLA.
• You are not sure of your dates and want an accurate due date.

NT Scan Price in Ahmedabad: What the Charge Depends On

I do not list a fixed figure here, because the total depends on what your screening includes. The hospital gives current charges on request - call +91 90545 74829 or ask at the Divine Women's Hospital reception when you book.

What changes the charge:

• Scan alone or full combined screening - the double marker blood test (free beta-hCG and PAPP-A) is a laboratory charge in addition to the scan.
• One baby or two - in twins each baby is measured and assessed separately.
• Pre-eclampsia screening - uterine artery Doppler, and PlGF where that blood test is used.
• Add-on tests - NIPT, if you choose it, is a separate test processed by an outside genetic laboratory.
• Further steps - counselling, CVS or an early fetal echo are separate items, needed only if the result calls for them.

When you enquire, say whether you want the scan by itself, or the scan with the blood test and pre-eclampsia screening. Then the figure you are given will match what is actually done.

Common Beliefs About the NT Scan, Corrected

Questions Patients Often Ask Me About the NT Scan