I haven't really asked anyone yet but this has been bugging me. When I went for my 12wk0d appointment, I had my ultrasound down and there was this little circle next to my baby. My ultrasound tech typed 'yolk sac' next to it to save in the files and then said, 'well, I don't see two.' This little circle 'yolk sac' has been on my mind and I have been wondering what it is. Can anyone give me an answer?