I did my first IUI as a natural cyle. The second I used clomid and the tirgger shot. This third time I took femara and the trigger shot. Your RE may want you to try natural the first time if he didn't prescribe anything-that may do the trick. Good luck!
I agree with docsaf normally your RE will tell you if you need to take drugs before an IUI. Are you just doing a natural IUI? Also are you using OPKs or the trigger shot? GL I hope this IUI brings you a BFP :)
Didn't your doctor prescribe something? Before my first IUI, My RE prescribed 50 mg of Clomid CD5-9. Before the 2nd IUI, my RE prescribed 50 mg of Clomid, CD3-7. Good luck!