There are risks involved, but these can depend on a number of different things that you may or may not know until after the u/s. each persons situation is different. It depends on how much experience the doc, turning bubs has at doing that. How much monitering is going on to ensure everything is going right. Why you bubs may not have turned in the first place - which is the reason for the u/s (some bubs have short cords, or knotted cords or cords wrapped around necks - but this is determined by u/s before attempting to turn bubs).

Talk with you midwife and doc, ask what they would advise you to do, but make up your own mind, and don't feel pressured into trying to turn bubs if you don't want to - but if you want to and your midwife and doc agree, then by all means go for it.

Also ask what your options are if bubs doesn't turn. some hospitals will only do c/s if this is the case. others will allow you to make the decision between trying for a vaginal birth or a c/s.