11-14 Week (Nuchal Translucency) Ultrasound Results

If you had a 11-14 week (nuchal translucency) ultrasound, you might be wondering what your results mean and possible next steps.

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| What the result means

A pocket of fluid behind the baby's neck is measured at the time of the ultrasound. This pocket of fluid is also called the "nuchal translucency" (NT). When there is an increased amount of fluid from what we typically see, there is a higher chance for the baby to have a genetic condition or another health issue.

The cut-off for the nuchal translucency measurement is 3.5 mm. If your measurement is less than 3.5 mm, this is considered "normal". If your measurement is 3.5 mm or more, this is considered "increased".

The ultrasound also looks at the baby's body parts, like the heart and the brain. Some major birth defects can be seen at this stage. A later ultrasound will take a more detailed look at how the baby is growing and developing.

"Normal" NT measurement

If you were told your NT measurement is "normal" and your prenatal genetic screening results are "screen negative" or "low risk", it means there is a lower chance for your pregnancy to have certain conditions. It is important to know that no test can look at everything. A normal result does not guarantee a healthy baby.

"Increased" NT measurement

If you were told your NT measurement is "increased", it means there is a higher chance for the baby to have a genetic condition or another health issue, including:

A chromosome difference, such as trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome).

Another genetic condition.
A birth defect (like a heart defect, or a problem with the growth of the bones).

The pocket of fluid will most likely disappear and will no longer be seen in future ultrasounds. It is also possible that the pocket of fluid will remain about the same or will increase even more. In some cases, there will be build-up of fluid seen in other parts of the body (such as lungs or under the skin). When this happens, it can be a life-threatening situation no matter what caused it.

An "increased" NT measurement does not mean there is definitely a problem with how the baby is growing and developing. Many babies with "increased" measurements are born healthy.

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| Next steps

You should be offered an appointment to a genetics specialist if your NT measurement is "increased". A referral to a regional genetics centre should be made even if the results of your other prenatal screening tests were "screen negative" or "low risk".

Find a Regional Genetics Centre

The genetics specialist will discuss your result in detail, provide support, and review options for more testing. Your options might include:

Diagnostic testing

Diagnostic testing is the only way you can know for sure before birth if the baby has a chromosome difference. Diagnostic testing might also include testing for other genetic conditions.

Non-Invasive Prenatal Testing

Non-Invasive Prenatal Testing (NIPT) is funded by OHIP when the NT measurement is increased. Keep in mind that NIPT does not look for as many genetic conditions as a diagnostic test, and the information from NIPT is not definitive.

18-22 week (detailed anatomy) ultrasound

A 18-22 week ultrasound checks how the baby is growing and developing. This ultrasound may also be done earlier depending on the genetics centre and how far along you are in the pregnancy.

Fetal echocardiogram (special ultrasound of the baby's heart)

A fetal echocardiogram checks the structures of the baby's heart and how it is working. This can be done at 18-22 weeks of pregnancy, or earlier. The timing of the fetal echocardiogram depends on the genetics centre and how far along you are in the pregnancy.

If the above testing is all normal, most babies will be born healthy. It is important to remember that no test can look at "everything", and a healthy baby can never be guaranteed.