There are some factors that can affect the success of your scan, the most common being your baby's position. Baby's have a mind of their own and sometimes do not want to smile for the camera. However, in this case we will ask you to take a gentle stroll and come back free of charge to see if baby has changed position. A high BMI can also affect the quality of the images as can reduced amniotic fluid. The amount of room baby has to move around will also affect the success of your baby scan. If you are having your scan at, for example, 34 weeks, it may be more difficult to get images of baby.