Amnio-centisis (sp?)

Hi everyone. Im wondering how many of u know alot about amnio's? Most of u may have read, but I am just over 17 weeks pregnant and my test results on the aplha protein test came back 'abnormal' or low so it puts me at 'high risk' for down syndrome. Anyhow I was really scared at first but I am getting a little better about it now. So many people have had that result and had healthy children. He said outta 400 'abnormal' test results, only 1 was down syndrome. Also my sis works w/ 3 women who all had bad results and they had healthy children. So I am thinking its pretty unlikely for the baby to have it. He said the ultrasound shows a healthy baby so far. But anyhow, now to get my ultasounds tho, sense it was abnormal I have to go to a special place like an hour away where they can do heart ultrasounds. My doctor reccomended doin the amnio (where the long needle goes in to draw fluid from the sac) he said this way he will know if it has it or not and be more prepared...But my moms friend had a miscarriage from the amnio and the doctor said its unlikey, but it is possible, however your body responds to the test. So I believe ive decided against getting the amnio but im just wondering what u all think. If it did have down syndrome the doc couldnt fix it anyhow... Thx