Essentially, the risk of infection is the same as if you're not pregnant, but then it's a bit like avoiding certain foods because they might have a bacteria that won't hurt you, but will hurt the baby - you stay on the safe side just to be absolutely certain.
Not exactly Gothmum . Because of the immunosuppression that takes place when pregnant, you are actually more susceptible to infection in the first place (even with proper management of a new piercing or tattoo), and your body is less able to naturally fight any infection whilst pregnant. So whilst it's true that the baby can be adversely affected by any infection that you get, the effect to the mum is also more significant than if she was not pregnant.