Surprise twins?


Has anybody ever had their first ultrasound show one baby but went back for another ultrasound and found two babies? I'm asking because my Doctor said my uterus was larger than it should be for my gestational age. I've just had a feeling of twins and everybody always says that's the first sign they had of twins, they just had a feeling. My baby was measuring exactly what he/she should be for their age. I'm just curious if this has happened to any of you.