Does Taking Steroids Cause Early And Short Periods?

i was put on predisone 5mg dosage 2x every 4 hrs for a herniated disc. started last tuesday..my period was due on friday and came but was done by saturday lunch time. i normally have very heavy periods. could this be a result of the steroid? there is a small possibilty that i could be pregnant as well but i've been trying for a while and have not been successful.