i cant imagine there ever being a 0% chance given , there is always a chance of this or that. your numbers sound fine, and i would try to relax.
im the one adgal was talking about. my dd is 7 weeks old and has down syndrome. i was 38 when i had her and my nuchal fold was 5.3 with a risk of 1:3. i did have an amnio and im just the type of person that had to know before. not to consider terminating, but to prepare and heal before the birth. my dd is the most precious little girl ever! its not as scary as you think, we all have a preconcieved idea of what down syndrome is like then this little angel is born and you think "oh its really ok!".
i wouldnt stress and worry. the drs will always lay it down for you in number this and ratios that. congrats on your pg!! i hope you have an easy pg and a healthy baby boy or girl!
I like adgal had a good NT number (1mm), but it was the blood work that got me. My risk was around the same as hers. I was considering an amnio, but didn't really want to go down that road. When I went in for the quad test I got my good news. My risk jumped to 1:1075. To top it off the ultrasound was perfect when the time came and I seem to be having a perfect little girl.
Just try to take a deep breath and wait for the next step. Will you be having quad screening next, or maybe that has already been done... You may find some reassuring news there.
I had the opposite problem I was 40 when I was pregnant with my son, and he was born just before my 41st birthday. NT fold was around 2 if memory serves me correctly (I would have to look at my journals to know for certain), but anyway, it was within what they considered normal parameters. When my blood work came back, my odds of DS were 1:13. There were no soft markers...nasal bone was present, etc. I still opted for amnio and results came back that I was having a typical baby boy...in other words, no DS. I don't think the nucheal fold in your case is much to worry about..it is still within what most consider normal range. And to have odds of 1:258..well, I know I wouldn't worry about that at all. Those are great odds!
Should you choose amnio, I can tell you that my experience with it was problem free. It was scary to think about, and of course I was afraid of m/c, but in all honesty I have had more pain getting freezing at the dentist (and I am petrified of needles!). It was very quick and I just took it easy for a few days. It is a big decision, and one that should not be taken lightly. Whatever you choose, I wish you well!!! BTW, I am now planning on baby no. 2...don't let age worry you too much. Yes, our odds are higher, but still very much in your favor. And if it is DS...a dear friend of mine on here has the most beautiful perfect little girl you have ever seen...with DS. I know she will chime in here and tell you that as far as she is concerned, she won the lottery (I am quoting her here).