Letrozole even if ovulating?

Luna • Mother of a 3 yr old boy 👦🏻 pregnant with #2 July 2020

I am about to start taking Letrozole 5mg for 5 days. I do ovulate, so I really don’t understand why my doctor is putting me on it. I just did my first IUI, and of course it failed. Didn’t take any medication for that one. And this is probably going to help me for my second IUI. I just thought Letrozole is supposed to help you ovulate, but I do. I am confused 🤷‍♀️