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 my NIPT 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 also concerns on your 18-22 week ultrasound than if you had a normal ultrasound.
What are my next steps?
If your NIPT result is "high risk" you should be offered a referral for genetic counselling to review your options.
Only invasive diagnostic testing (chorionic villus sampling or amniocentesis) can tell you for sure if your baby has one of these chromosome differences during the pregnancy. A detailed anatomy ultrasound at 18-22 weeks of pregnancy can also be helpful, as it looks for the presence of structural differences in the baby. However, a normal ultrasound does not mean the baby does not have the chromosome difference.
Diagnostic testing can also be performed after birth, if invasive diagnostic testing is not done during pregnancy.
Refer to the prenatal screening pathway for more information.