Hi Dipsy
At 27 years old I would say that you are a low risk of having a Downs syndrome child. The test your doctor is talking about is done by an ultrasound and measurers the fluid at the back of your baby’s neck. This test will not tell you that your baby has downs but it can indicate that your baby is at a higher risk of being born with downs syndrome.
Amniocentesis does increase the chance of miscarriage by between 1% and 2% however it is a much more accurate test.
One of the things you need to consider is, should the test indicate that your baby does have downs syndrome would you have a termination? If the answer is no then there is no real point in testing for it. As I said earlier you are young and if there are no other risk factors such as a downs syndrome child in your family then i would say that you are at a low risk.