Another scan for the imbilical cord

Went to the specialist to check my cervix again. Since great news on that it lengthen from 4 to 4.2. So we aren't worried about that now. The dr did see that the imbilical cord only had 1 vessel instead of 2 or 3 so we go back in 6 weeks to check on that. He said it could mean down syndrome but we had blood test rule that out so he threw that out the window but he said if it's still that way next scan it will mean I will have a small baby. I typically have small babies anyway. He hide his face for the 3d scan.