depends on your doctor. when i had my first ivf, i was on regular lupron, menopur, follistim etc. on my 2nd cycle, they changed the lupron to the microdose lupron which i had better result than the first one because i ended up having IUI on the first because there were not much eggs, just 1 i guess. feel free to ask your infertility doctor. you will get answers.
A medicated cycle can increase your chances relative to trying on your own. I would give IUI another chance. Also, you may talk to your RE about changing your meds or increasing your dosage to improve your chances.
Good luck!