Infertility. Go for iui. please suggest.

I am 4yrs married girl and no baby yet. Taken follicle study for 6 times and we naturally tried on ruptured date but no luck. My husband semen analysis are normal. I have thyroid problem so taking Eltroxin 100mcg. My lmp was April 4th. Still period is not coming. After tested urine sample, hcg blood result negative. So my doctor gave Derivy on 27th may for 3 days twice daily and period not came. So doctor taken pelvic scan on 13th june and said uterus, both ovaries are normal with endometrium thickness 7 mm and no pcod. And mentioned developing follicles in both ovary. I am wondering how ovulation will happen since I haven't get period yet 73 days overdue. My doctor suggested to check on follicle growth after 5 days. once its growth well and ruptured can we go for IUI.. Please suggest..