Fibroids in pregnancy

Has anyone had fibroids during pregnancy? We just had our 12wk scan and the sonographer thinks i have a large fibroid (i had to google it as she didnt elaborate any further). I have a doctor's appointment next week but from what i can gather online, it can be fatal to bub depending on location and whether it grows (i didnt see in my dating scan 2wks prior). Pretty scared but would like some facts and/or experience from others so that i can be prepared. Thank you xx