Answer:
The drug Prednisone is one with an awfull lot of side effects. Side effects being severe and side effects being not so severe. The positive effects of the drug for those who need it will in many cases outweigh the bad.
During my research on internet I found contradicting stories as to the safety of the drug during pregnancy. The side-effects recorded for the drug does however not include pregnancy and birth defects. This could of course be due to lack of subjects to make a statistic.
One informationpage I went to states: Women who need prednisone during pregnancy usually have no problems with their offspring-- except the pediatrician needs to observe them to ensure their adrenal glands develop appropriately.
Prednisone is a drug that after a while deactivates the bodys own production of adrenalin.
This will most likely be transferred to the baby during pregnancy and so after giving birth your baby might/will need to be weened off the drug very slowly.
Please ask your doctor if there are any "safer" alternatives.
I have however not seen any red flashing warning signs in my research regarding the drug and pregnancy. This should imply that the drug is "fairly" safe.