should or should not take prednisolone during pregnancy?

Hi Everyone, i just received happy news that i am pregnant for 6 week. i was so happy but at the same time i am worry about this pregnancy. i have autoimmune disease (recurrent mouth ulser) and if not pregnant i have to take 20mg prednisolone to reduce the inflamation in my mouth and skin.but now i am pregnant. it is safe for my baby if i take the prednisolone?. May i know is anyone ever had same problem?