Need advice—high risk for trisomy 21, possible vanished twin
I’m 32, 12w5d pregnant, and received my NIPT results that came back as high risk for trisomy 21. I took drew blood for it at 10 weeks. I did the Unity test and it shows as 9 out of 10 as the risk. They don’t have a specific PPV listed and I’m pretty sure they give 9/10 for everyone. My fetal fraction was 9.5%. I also might have had a vanished twin (more on that later).
I’ve done what I think is all the research that I could possibly do and I keep getting completely contradicting information. I see the NIPT calculators that are specific for trisomy 21 and I get a PPV that’s at about 68%-84% depending on the calculator used, but I know that’s based on 16 week gestation.
And then some parts of the internet and research based articles state that there’s always a very very small percentage that NIPT for trisomy 21 is a false positive. Like less than 1%. I wish there was some kind of solid stat on how many women do further testing and establish it was a false positive.
I guess statistics aside, the only helpful information will be a solid yes or no from either CVS or amnio. My issue is that i MIGHT HAVE had a vanished twin. My doctor “wasn’t sure” if the empty sac was from a vanished twin or subchorionic hematoma. I never ended up bleeding at all though. No fetal pole was ever seen and it was spotted on a 7.5 week ultrasound. I also don’t really trust my doctor and will be changing providers asap.
So my questions are:
do I get a CVS so i don’t wait to be 17 weeks pregnant after amnio and go through a tough, surgical second trimester abortion?
Or is it worth it to do the amnio to rule out mosaicism or something related to this possible vanished twin issue?
If I see markers on the ultrasound I do should I just do the CVS and move forward based on those results?
Thank you!