I have 3 books all stating differing risks of miscarriage. In 'What to expect when you are expecting' its 1:1600, in the 'Rough Guide' its 0.5:100.
I had my OSCAR and the risk is 1:765. I am 39. I need to be more sure due to my husbands illness which may get worse in later years - are there other tests that are no evasive I can have to find out more on my risk factor, or it the only way an Amnio. I am at 13.5 weeks today.
The risk varies from clinic to clinic, so your best way of finding out is to ask your mw, but I believe it's usually between 1 in 100 and 1 in 200. Your results are great though, amnio is usually recommended if your result is greater than 1:100, but obviously your circumstances are different.
An anomaly scan may show conditions associated with chromosomal abnormalities, such as heart or bowel defects.