I had a NT measurement of 4.2, normal blood tests but at the age of 41 that gave me a DS risk of 1/37. I had an amnio done at 16 weeks and all my results showed no abnormality found. I was told a 4.2 measurement was considered a "little high" but the OB could have been trying to soften the blow.

Amnio has half the miscarriage risk of CVS therefore I went for that and I found that it was completely painless, didn't even get any cramping afterwards. It's not a bad experience at all so please don't be scared of it.

Do be prepared for it being expensive though. Mine cost about $50 shy of $1000 all up. Around $200 for the scan and the procedure (paid to the doctor) then $550 for the karyotyping (results available in two weeks) and $200 for the FISH results. I'd recommend getting the FISH results as it does put your mind at rest and waiting 24 hours is a killer, waiting two weeks would be far too stressful. You can't claim the FISH on medicare but you can claim the rest - think I'll be out of pocket around $500 but it's well worth the peace of mind.

I've now been told because of the abnormal 12 week scan I will also have to have an extra scan at 32 weeks because sometimes a baby who has had a higher NT measurement can end up with slow growth so don't be shocked if you get told that later on.

If they give you a 1/100 chance of downs it means 1 woman out of 100 with the same result as you will have a downs baby, but it can't tell you which woman will. That of course means 99 of those women will have a "normal" baby. If you get anything over 1/300 they will recommend either an amnio or a CVS.

Try not to stress, it may be nothing.