Finding the right tests…
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Finding the right tests…
Sonography
NT.NB SCAN is done early in pregnancy, usually between 11 and 14 weeks, and looks at two specific markers: the thin layer of fluid at the back of your baby's neck, called the nuchal fold, and whether the nasal bone has started to form. Neither marker gives an answer by itself. Combined with a blood test that checks specific proteins and hormones in your blood, the two ultrasound readings feed into a risk estimate for Down syndrome and a small number of other chromosomal conditions. This scan doesn't diagnose these conditions. It flags whether your personal risk sits higher or lower than average, so your doctor can discuss whether a further, diagnostic test makes sense for you.
This scan measures the fluid layer at the back of your baby's neck and checks whether the nasal bone is visible, then combines both readings with a blood test result into a single risk estimate for certain chromosomal conditions. It doesn't diagnose anything on its own.
NT.NB SCAN is done early, usually between 11 and 14 weeks, before many other pregnancy scans are even considered. At this stage, your baby is small enough that two specific markers can be measured with unusual precision: the nuchal fold, a thin layer of fluid at the back of the neck, and the nasal bone, which has typically started to form by this point.
Neither marker is read alone. A thicker-than-expected nuchal fold, or a nasal bone that's harder to see than expected, each raise a flag on their own, but combining the two with a blood test measuring specific proteins and hormones gives a more reliable risk estimate than either piece by itself. This combined approach is standard first-trimester screening for Down syndrome and a small number of other chromosomal conditions.
A result here is a risk estimate, not a diagnosis. It tells you whether your personal risk sits higher or lower than the general population, based on your markers and blood results together. A higher-risk result doesn't mean your baby has a chromosomal condition, and a lower-risk result doesn't rule one out completely. Either way, your doctor uses the result to discuss whether a further, diagnostic test would make sense for your situation.
It measures the fluid at the back of your baby's neck, called the nuchal fold, and checks whether the nasal bone is visible. Both readings are combined with a blood test for a risk estimate.
It's usually done between 11 and 14 weeks, a window when these specific markers can be measured accurately.
No. It's a screening test that estimates risk, not a diagnostic one. A higher-risk result would usually be followed up with a diagnostic test if you and your doctor decide that's the right next step.
The blood test measures separate proteins and hormones that, combined with the ultrasound markers, give a more reliable risk estimate than either test gives on its own.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
It doesn't mean your baby has a chromosomal condition. Your doctor talks you through what the result means for your specific situation and whether a further, diagnostic test makes sense.
Yes. It's a standard ultrasound scan using sound waves, with no radiation exposure and no known risk to you or your baby.
There's no single preparation that applies to every patient. Ask your doctor or the centre what they'd like you to do beforehand.