I'm 14 weeks and a day now and our baby's NT was 3.9mm and baby was upside down. I had another scan with a specialist who calculated based on my age (30) and the NT being 3.9mm we had a 1 in 343 chance the baby will be born with downs syndrome. The sonographer then scanned me to check everything else the structure etc (although she didn't re measure the NT) she said everything else looked fine. The next steps for us is to go to the JR hospital to have a specialist take a look at the babies heart (as enlarged NT can be a sign of cardiac problems) and if that is ruled out and there are no issues we will have a scan on the baby every 2 weeks until mid March. If there are no issues at this point the sonographer advised the blood test but I know this has limitations (it won't pick up on everything). I'm seriously considering after the heart scan, if all is well then asking for an amnio so we don't have this cloud of uncertainty looming over us for two months. I would be so grateful for some input from those who have had an amnio and how it went to help me make this decision.