1st Round of Femara after 4 Clomid Rounds

Maddie
I have polycystic ovaries and have bee TTC for several years. I have been on 4 round of Clomid. I ovulated 3/4 of those rounds. My new doctor is switching me to Letrozole/Femara. Has any one had success conceiving while taking Femara when you didn't on Clomid? I could use some hope - I don't have much anymore. Thanks ladies!