High risk for down syndrome for a second time

I'm hoping someone can give me some advice or atleast share their experience with me to put my mind at rest. I have 2 boys and am currently 18 weeks pregnant with my third. on my second pregnancy it came back as high risk for downs 1 in 49, had the amnio, all results clear and i have a prefectly healthy 15 month old. Great! My third pregnancy has also come back as high risk for downs 1 in 58. I'm trying not to worry as i know how inaccurate these blood test are my 15 month old is proof of this, however i would like to know is it normal to have two consecutive pregnancies come out high for down synrome? I have opted for the amnio again because i just need to now, but i have convinced myself i may not be so lucky this time.I was 34 with my second and i am 35 and will be 36 when i have this current baby. thank you in advance

[GenevieveDove]

From what I've read the two big risk factors for having a high risk of a child with Downs Syndrome are the age of the mother (the older the mother, the more likely the child could have it.) and a genetic chromosomal abnormality.   You could ask for a test to determine if you carry the genetic abnormality that leads to a higher risk of Downs Syndrome.  I've got no direct experience with this, but I wish you the best.  That's got to be stressful!