That sounds so cute a baby sucking their thumb.
I got to watch a live 4d one of my baby and he sucked his thumb and yawned , he's so perfect I love him :)
I went for an ultra sound at about 22 weeks and she yawned and it was cute!!
When we had the ultrasound of my daughter, you can actually see her punching my stomach in te photo. You can see her little fist and the indent where she hit me. When we saw my little boy, he was sucking his thumb
When I had my u/s at 28+6 my baby boy looked like he was waving to us. It was super cute. Then he started to rub his eyes, I couldn't help but get teary eyed and so did my boyfriend. ♥
Aww im going for a 3d sonogram this weekend...