Umbilical chord around baby's neck

Hi ladies! Today we paid for a 3d ultrasound to see our baby boy. Midway through the ultrasound we watched as my little boy wrapped the chord around his neck like a scarf. Should I be worried? I'm 26 weeks so I know there is still wiggle room for him to get the chord off of him but I can't help but feel concerned. The place I went to was a private place, it wasnt associated with my OBs office. Should I call my doctor? Do you have any personal experiences like this you can share??