High detection rate for Down syndrome
When combined with maternal blood markers, the NT/NB scan detects around 85‑90% of Down syndrome cases with a low false‑positive rate – one of the best screening tools available.
The NT/NB scan, also known as the first‑trimester screening ultrasound, is performed between 11 weeks and 13 weeks + 6 days of pregnancy. It measures the nuchal translucency (NT) – the fluid‑filled space at the back of your baby's neck – and checks for the presence of the nasal bone. Together with maternal age and blood markers, this scan provides a powerful, non‑invasive risk assessment for Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), and Patau syndrome (Trisomy 13).
This is one of the most important screening tests in early pregnancy. An increased NT or absent nasal bone can indicate a higher likelihood of a chromosomal abnormality, allowing you to make informed decisions about further diagnostic testing (like CVS or amniocentesis) if you wish. The scan is safe, painless, and gives you valuable information about your baby's health.
At Amytri, we perform NT/NB scans to the highest standards, following international guidelines. Our consultant radiologist has extensive experience in fetal medicine and uses advanced ultrasound equipment to obtain precise measurements. We explain the results clearly and support you in understanding what they mean for your pregnancy.
The NT/NB scan is not a diagnosis – it's a screening tool that helps you understand your baby's risk and choose your next steps with clarity.
When combined with maternal blood markers, the NT/NB scan detects around 85‑90% of Down syndrome cases with a low false‑positive rate – one of the best screening tools available.
If the scan shows an increased risk, you can opt for chorionic villus sampling (CVS) or amniocentesis for a definitive answer – all within a time frame that allows for informed choices.
For the majority of pregnancies, the scan shows normal NT and a present nasal bone, providing strong reassurance that the baby is at low risk for these conditions.
Our NT/NB scan follows strict quality criteria to ensure reliable results.
We measure the fluid‑filled space at the back of the fetal neck. The measurement must be taken at the correct gestational age and with the fetus in a neutral position – our expertise ensures accuracy.
We check whether the nasal bone is present or absent. In Down syndrome, the nasal bone may be absent or hypoplastic in a significant proportion of cases.
We confirm that your baby is between 45‑84 mm (the window for NT measurement), ensuring the scan is performed at the correct gestational age.
We examine the fetal brain, heart, abdominal wall, and limbs for any major structural anomalies that may be visible at this early stage.
If you're expecting twins or more, we assess each baby individually – because NT measurement and risk calculation differ in multiple pregnancies.
We integrate your NT measurement, nasal bone status, maternal age, and (if available) first‑trimester blood markers (PAPP‑A and free β‑hCG) to give you a personalised risk estimate.
Call or WhatsApp us – we recommend booking between 11 and 13 weeks + 6 days, based on your dating scan.
Drink water and avoid emptying your bladder for about an hour before the scan – this gives a clearer view.
We perform the scan on your abdomen. If the baby's position isn't ideal, we may gently ask you to walk around or use a transvaginal probe for better views.
We explain your NT measurement and nasal bone findings, calculate your risk score, and provide a comprehensive report for your records and your doctor.
This scan is a standard part of first‑trimester care for most women, but it's particularly valuable in these situations.
Advanced maternal age is associated with a higher risk of chromosomal anomalies – this scan gives you a personalised risk estimate.
If you've had a previous pregnancy affected by Down syndrome or another trisomy, early screening is essential.
If you or your partner have a family history of chromosomal conditions, this scan provides important early information.
If a previous scan raised any concerns, the NT/NB scan can provide further clarification.
Twins or triplets require special consideration – we assess each baby individually and explain the nuances of risk calculation.
Many women choose this scan simply for peace of mind – knowing that they've done the recommended screening and received a low‑risk result is deeply reassuring.
The NT/NB scan requires specialised training and experience to obtain accurate measurements. Our consultant radiologist is accredited in fetal medicine and follows international guidelines from the Fetal Medicine Foundation, ensuring you receive the highest standard of care.
The NT/NB scan can be an emotional experience – having your partner by your side can provide comfort and shared understanding.
We encourage partners to attend. We explain the measurements and what they mean, answer any questions, and provide printed images. If the scan requires a transvaginal approach, we ensure your comfort and privacy at all times.
The NT/NB scan is an ultrasound performed between 11 and 14 weeks to measure the nuchal translucency (the fluid at the back of the baby's neck) and to check if the nasal bone is present. It's a key part of first‑trimester screening for Down syndrome and other chromosomal conditions.
No – it's a non‑invasive ultrasound, completely safe for both you and your baby. It uses sound waves, not radiation.
The results give you a risk estimate (e.g., 1 in 1000 or 1 in 200). A lower number means a higher risk. Most results are low‑risk, but if yours is higher, we'll discuss further diagnostic options like CVS or amniocentesis.
For the most accurate combined screening, we recommend first‑trimester blood markers (PAPP‑A and free β‑hCG), usually taken around the same time. We can coordinate this for you.
It's common for the baby to be in a tricky position. We may ask you to walk around, drink some water, or have a transvaginal scan for better views. We won't rush and will ensure the measurements are reliable.
No – you can book directly. If you're under obstetric care, we'll share the report with your doctor.
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