Thanks for the comments. Yeah, I kept thinking maybe it was implantation bleeding too, even did 2 HPTs which were negative :-(
At least it may help me predict ovulation/cycle length better. I ovulated about the same time without Femara but my luteal was between 11-13 days. Now I know it could be exactly 15 days (I O'ed on cd 15).
Sounds like you are in the TWW? I'll keep my fingers crossed.
last month was my first month and femara. I had the same spotting, and my cycle was also 30 days. (usually mine is 35 though, so 30 was better for me). . . the spotting bothered me too, I kept hoping that it was implantation bleeding. But no, finally af came full force. This is my second month on it. I o'd the same day this day as last month, so expect the cycle will be 30 days again. Good luck with your IUI!!