Baby scan shows baby has big tummy

Hi, I was told that my baby's tummy is slightly bigger than usual. And the doctors asked if I did any downsyndrome test, which I did not. I am currently 33weeks pregnant. Any of you guys ever been told that your ultrascan shows that baby's tummy is bigger than usual? I'm googling and the answers are all over the place. #firstbaby #1stimemom #1stpregnnt #advicepls #1stbaby