u don't need to warry too much
the obe (婦科) told me that it is very common
almost every woman has such firbord inside
u may not discover them until u are checked by ultra sound. it would not harm u
The size varies as the level of 荷爾蒙, particular when u pregnant.mine is about 9 cm!
it may lower your chance to pregant, and u may have higher chance of miscarrage if it is very big.
so consult your physcian before thinking of having baby.