I had several during my first pregnancy. I had a great pregnancy but they grew and my daughter flipped breech so I ended up in a c-section.
Not all fibroids cause problems. Not all fibroids grow abnormally large. There are a few risks with them depending on where they are in your uterus, how many are present and how big they grow.
It is possible for some people to have a pregnancy that is completely "normal" with fibroids. :)