Hello Doctor, I am 33 years old and 14 weeks pregnant for the first time following IVF. I had my first trimester screening last week ( at 13 weeks) which included the NT measurement with the PAPPA and beta-HCG blood tests. I received a call from the genetic counselor on Friday saying that my risk for Down's Syndrome is 1:110. Fortunately, I was able to get the newer blood test, versus CVS or amnio, that looks at chromosomes in my blood from the baby and can determine whether or not the baby has trisomy 21. I will have to wait two weeks for the test results and I am extremely anxious and haven't slept well or been able to concentrate since I heard the result. The NT measurement was 2.2 and the PAPPA I believe was .70 or .75 and the beta-HCG I believe was 1.8. I don't have the results in front of me, but I am fairly confident those were the numbers they showed me Friday. The counselor said the numbers were in the normal range, but that the decreased PAPPA compared to the HCG increased the risk. I guess my question is after reading about the screening test and the 5% false positive rate, is my risk truly 1:110 or is it only 5% chance that the fetus is unaffected? I also believe the sonographer noted the nasal bone to us during the scan, but now I am not sure. Would that be a positive sign? Any help clarifying would be very helpful.
Thank you!