High Risk NIPT Results
You have received a "high risk" result on your non-invasive prenatal testing (NIPT) and you may have lots of questions about what the results mean for you and your baby, and what next steps you could consider.
What Does a "High Risk" NIPT Result Mean?
A "high risk" result means that the chance that the pregnancy has trisomy 21, trisomy 18, trisomy 13 or a sex chromosome difference is significantly increased. It is important to be aware that a "high risk" result does not mean for certain that your pregnancy has a chromosome difference, since NIPT is a screening test.
How Accurate is the Result?
We know that the accuracy of NIPT depends on which chromosome difference you got a "high risk" result for. For example, a "high risk" result for trisomy 21 is more likely to be a true result than a "high risk" result for trisomy 13. This is because NIPT is most accurate for trisomy 21.
"High Risk" Result for Trisomy 21
Out of 100 people who get a “high risk” result for trisomy 21, 96 actually have a baby with trisomy 21.
"High Risk" Result for Trisomy 18
Out of 100 people who get a “high risk” result for trisomy 18, 93 actually have a baby with trisomy 18.
"High Risk" Result for Trisomy 13
Out of 100 people who get a “high risk” result for trisomy 13, 71 actually have a baby with trisomy 13.
The accuracy of your NIPT result also depends on whether there are other factors that make it more likely for you to have a baby with a chromosome difference. For example, your "high risk" result for trisomy 18 is more likely to be true if there are concerns on your 18-22 week ultrasound.
What Are the Next Steps?
If your NIPT result is "high risk" you should be offered a referral to a specialist in genetics to help you understand your results, provide support, review your options, and arrange further testing as needed.
As the next step, you can choose:
| Diagnostic testing |
| Diagnostic testing (usually through chorionic villus sampling or amniocentesis) is the only way you can know for sure if your baby has a chromosome difference during the pregnancy. |
| Detailed anatomy ultrasound (18-22 week ultrasound) |
| The detailed anatomy ultrasound checks how the baby is growing and developing and is done at 18-22 weeks of pregnancy, or earlier, depending on genetics centre and how far along you are in the pregnancy. This ultrasound can give you additional information; however, a normal ultrasound does not mean the baby has no chromosome difference. If you already had a detailed anatomy ultrasound, you may have the ultrasound repeated at the genetics centre. |
| No more testing during the pregnancy |
| If that is your choice, diagnostic testing can be done after birth to learn if the baby has a chromosome difference or not. This testing is done through a sample from the cord blood at birth, or through a regular blood sample from the baby. |
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