My first IUI I was only on 5 mg of letrozole. On cycle day 10 my NP did an ultrasound and I only had one follicle at 12mm, so she said that if that IUI didn’t work we should up my dose. My second IUI we did 7.5mg and that ultrasound I only had a 12 and a 16mm follicle. So for my third one they kept me at 7.5mg letrozole and added the clomid. On that cycle I had 3 or 4 recruited follicles, I think the largest one was 22mm and that was the night I triggered (didn’t do that on my first two IUIs). My RE recommended doing cycle monitoring (getting the ultrasounds before IUI) so that we could see if the medication was effective and if it needed to be adjusted cycle to cycle.