Everything You Need to Know About a PET Scan
October 29, 2024
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If you’re going through the early stages of pregnancy, the list of tests and scans available can be overwhelming. One scan that often causes confusion is the nuchal translucency ultrasound.
This optional scan helps medical providers screen for congenital conditions, such as Down syndrome, though it is not a definitive diagnostic test in and of itself. In this guide, you’ll learn what to expect, how the process works and what the results may mean.
The nuchal translucency scan helps assess risks for multiple genetic conditions, making it useful for your healthcare provider to see if additional testing or precautions are necessary. Here are some common questions about the NT scan, including what it is and when it should be scheduled.
Nuchal translucency refers to the elective ultrasound you can get in your first trimester. It is entirely optional, but most doctors strongly recommend having the scan. It measures the fluid found behind your baby’s neck. Depending on the amount, doctors can estimate whether the baby is prone to chromosomal abnormalities or other genetic variations. The results are not a concrete diagnosis but rather a way of factoring risks and predispositions, which helps you and your doctor determine what next steps to take.
The nuchal translucency measurement happens at the nuchal fold, the area behind your baby’s neck. When extra fluid is found here, there is a higher risk for conditions like:
Typically, the pregnant person will also have a blood test to further enhance diagnostic accuracy.
A prenatal ultrasound scan showing nuchal translucency
The nuchal translucency screening test is time-sensitive, so you’ll want to decide quickly if you’re interested in scheduling. The scan happens when your baby is at 11 weeks to 13 weeks along or when they measure 45-84 millimeters from the top of the fetal head to the bottom of the torso. Around 14 weeks, the fluid gets reabsorbed into the baby’s body, significantly decreasing the diagnostic capabilities of the NT scan.
Here, we’ve broken down what you can expect at your nuchal translucency and how the testing actually works so you can take the guesswork out of your screening.
Ultrasound is a safe, non-invasive imaging technique where the technician uses a handheld ultrasound wand called a transducer. After a conductive gel is applied to your skin, the wand is moved around your abdomen to bounce sound waves off your tissues and other internal structures. These “echoes” are then shown as real-time images on the technician’s screen. From there, they can take measurements of the fluid behind your baby’s neck and save the images for further analysis.
Your doctor will likely have you come to your appointment with a full bladder, as it can help improve sound transmission and tilt the bowel and uterus into better positions for imaging. You may feel a little pressure when the technician presses with the transducer, but it is not painful. Ask your doctor ahead of time if they have specific fluid recommendations.
Usually, the NT scan uses an abdominal ultrasound, but occasionally you may also need a transvaginal ultrasound for a better view. This is where the transducer is inserted inside your vagina, where it provides a more detailed view of your internal organs and uterus. The ultrasound technician will take measurements of your images, but they will have the doctor discuss any findings.
Here are some helpful questions you can ask during your NT scan:
Your nuchal translucency test is usually not the only diagnostic factor. Most healthcare providers recommend a first-trimester screening, which includes the blood tests mentioned earlier. Other factors considered include your age, family history, and even an absent nasal bone in your baby, which can be a strong indicator of Down syndrome.
The final data is typically expressed as a quantifiable risk value, such as a 1 in 500 chance of having congenital issues. Remember, your pregnancy ultrasound alone will not lead to a diagnosis. It will point you to other steps, such as further testing.
The nuchal ultrasound alone is about 70% accurate for Down syndrome screening. This accuracy can reach as high as 95% when combined with blood tests.
A pregnant person looking at their pregnancy ultrasound on PocketHealth
How quickly you get your screening results will depend on your medical provider and their policies or schedule. It also depends on whether the doctor wants to get your blood work back before giving the final figures or prefers to communicate updates on each separate test or scan. For the nuchal ultrasound, results typically come within a day or two. Blood test results can take longer.
If you’d like to review your results as soon as possible, you can use PocketHealth to quickly and easily access your images and report as soon as the radiologist finishes their assessment, often before your follow-up appointment.
Because medical terminology can be confusing, we’ll explain what to expect from your nuchal results and what they mean.
The ultrasound technician initially interprets your images, but your doctor will be the one to go over the results with you. It’s common for doctors to wait until all first-trimester screening data is available, including the nuchal measurement, before discussing them, though this can differ depending on the doctor. Whether you discuss the results immediately or wait until all the data is available depends on your medical provider’s policies.
While waiting to hear from your doctor, PocketHealth Report Reader can help you understand the medical terminology in your imaging reports, making it easier to understand your results. It’s a helpful tool to stay on top of your health, but it does not replace professional medical advice. It’s a way to inform patients so that they can be better prepared to ask their doctor meaningful questions. Some examples of things to ask include:
To support you further in this process, PocketHealth’s MyCare Navigator offers valuable insights into your health. It provides personalized questions to ask your doctor so you can get the most out of your conversation and stay on top of follow-ups and screening methods.
The fluid measurements typically indicate anything more than 3 millimeters could mean a higher risk for genetic issues. Occasionally, medical professionals will use a slightly different baseline, but usually, 3 millimeters is the standard measurement.
If your fetal nuchal translucency has abnormal results, your doctor will likely suggest further testing and go over the options with you. Your baby is at a higher risk for congenital syndromes, but it is not necessarily an actual diagnosis. Some next steps to gather information may include:
The nuchal translucency should be performed between the 11th and 13th weeks of gestational age, before 14 weeks. It may be better to schedule your NT scan closer to 11 weeks if possible. Then, if something prevents you from making your appointment, you have time to try again within your testing window.
Typically, yes. By 14 weeks, the developing fetus will start to reabsorb the fluid that will be measured.
Here are some possible indications of Down syndrome in your unborn baby:
First-trimester screening usually consists of:
If any of these components of the combined first-trimester screening are irregular, further screening for genetic disorders can be discussed with your doctor.
Waiting for your results can be stressful. PocketHealth users can access their ultrasound images and reports faster and easier, so the wait is minimal. You also have all your imaging in one place, so if you ever need to switch doctors or send your ultrasounds to a specialist, you have them at your fingertips. You can even send them to family and friends who want a peek at your baby.
While PocketHealth doesn’t replace medical advice or provide official diagnoses, it is a valuable guide to understanding your health. Easy access to your imaging reports allows you to be better prepared for your next doctor visit, so you can have productive exchanges that help answer all your questions.
