The same thing happened with us. I got pregnant extremely fast after our first one was born. He was a premie. Due to my age at the time I was consiered "old" at 35. The high risk OBGYN let us know about the CPC he also stated it "was" and only an indicater of trisomy 18. He advised us to have an amnio. My husband and I both said that was out of the question due to the high risk of mis carriage. Our Obgyn then went over the ultra sound and found nothing else present but also said it was early to rule anything out. We were advised if we wanted to terminate the pregnancy quickly if thats what we decided to do because if the baby did have trisomy 18 he wouldn't make it. Well four years later our son did not have trisomy 18 and that because of the earliness of our ultra sound the cpc showed on the scan. We paid for an additional ultra sound out of pocket because the insurance company would not pay due to the fact we negated an amnio. Our monster is healthy and is annoying his big brother daily.