Can I take multivitamins that contain riboflavin while pregnant?

Yes but.... Riboflavin, pyridoxine and thiamine are all b vitamins and are usually safe while pregnant... In fact pre natal vitamins usually have these vitamins along with others and of course Folic acid which is wise to take prior to and during pregnancy. I would recommend you avoid taking mega doses of vitamins or many types of vitamins but taking your pre natal vitamins is wise.