Tattoo while pregnant?

Please read before commenting.

So. I work in a tattoo shop and we dont tattoo pregnant women/while they still breastfeed. As to why, they say there is a risk of infection.

Most people that come in, dont know about this, same with piercings.

My questions are for you people out there that have experienced any issues related to tattoo/piercing while pregnant, and what shops/doctors etc have told you as to why not.

What can go wrong? What diseases/infections can you get? Did you notice anything going wrong? Is there a difference as to when you do it (4 weeks vs 4 months?)

I have tried googling but there is little info aside from disease transfer due to dirty needles, and it might end in miscarriage, so want to learn more so we can give more informed answers!