To get a definitive 100% answer for chromosome abnormalities including Down syndrome, a prenatal diagnostic test is needed (chorionic villus sampling or amniocentesis).
For example, it tells us whether your baby has a low risk of having trisomy 13, 18 or 21, or whether your baby has a high risk of having trisomy 13, 18 or 21.
This test gives us an indication of whether we should worry about your baby based on these results.
This means that combined first trimester screening will not give us a definitive answer.
For example, this test will not tell us "no, the baby definitely does not have trisomy 13, 18 or 21" and, this test will not tell us “yes, your baby definitely has trisomy 13, 18 or 21”.
This testing combines the nuchal translucency ultrasound with specific blood tests.
Nuchal translucency ultrasound alone can also provide this risk assessment, but it is not as accurate as combined first trimester screening.
For more information of prenatal diagnostic testing, please go to: The nuchal translucency is the fluid found at the back of your baby’s head and neck, just beneath the skin.
The thickness of this fluid can be precisely measured and this is called the nuchal translucency (or NT) measurement.
She said she's known some to tell at 12w, but she said it's just too early to say with any finality that that's what you're having. What I said before was that my tech told me when we went in for the dating ultrasound, that techs won't usually tell until the 20 week ultrasound. Exactly..tech told me that wouldn't it be terrible if they told you one thing, and you come to find out later, it's a different one? Good luck at your appointment I had a friend who was told she was having a girl at something like 16 weeks and at the next u/s they found a penis! Of course, she loves the boys just the same but I would be so frustrated if I was told one thing and then another later. My sister-in-law said she knew all along she was having a boy with her first.