L.W.
Hi S. - To get the defined answer that you want (and to put your mind at ease) you need more objective information. An amnio is really the next step for testing - most OBs consider it the "gold standard" of antenatal testing. New data on amnios show a risk to the fetus which is much less than previously reported, as earlier studies were done without ultrasound guidance - essentially, a "blind" insertion of the needle without the benefit of a window into the uterus - clearly this would be more risky than a needle inserted with "sight". If you have a very experienced maternal fetal medicine specialist do your procedure - a high risk OB who has probably done 1000's of them - and ask whether they have had any poor outcomes - your risk falls even more. The results of the amnio will give you the answer either way as to whether your fetus has Trisomy 16. It is very rare, so the numbers are on your side. Good luck.