How Safe Is Taking Clomid And Duphaston Together?

Hi I am 34yrs old. I have been married 3yrs. Being trying to get pregnant for 2years now. Was told by the doctor that I had PCO from US scan but I do not have features in keeping with PCO Was initially placed on clomid then later some menogon injections. I had a cevical polyp twice following this.First one was taken out via surgery and was benign, second dropped out on its own, I have been off drugs for 10mths now. What do u advice about taking clomid with duphaston. Do i need to take metformin.