Second level II U/S results

I had my second level II ultrasound yesterday. I am almost 19 weeks. The good news is that the baby is perfectly healthy. But they did see a calcium deposit on the heart. They did not see any other markers indicating Downs. My NT measurement was still normal. This calcium deposit now increases my risk from 1 in 78 to 1 in 40. So now I am debating on whether or not to have an amnio, and I am leaning towards not having one. I would not terminate if I found out the baby had Downs since there is nothing else wrong. I think if I did find out it had Downs I would be really upset and depressed the rest of my pregnancy knowing my baby wouldn't be born "normal". I'm not the type of person who will worry constantly if the baby will be alright. I just have a feeling that it is fine. Also the risk of miscarriage with an amnio bothers me, since I had a miscarriage last year. Has anyone every heard of this marker and what the outcome was?

Oh by the way, ITS A GIRL!! DH was a little disappointed since he wanted a boy. I was a little bit too since I already have two girls from a previous marriage, but it really didn't matter to me. We are so grateful that she is healthy.

Michele