Q: When should I do IUI after the hCG shot?

A: Pregnancy rates are generally higher when insemination is done before rather than after ovulation. Doing IUI after ovulation would be too late as it doesn't get you pregnant.
A study (Fertility and Sterility, Volume 72, Number 4, pp. 619-622) reviewed pregnancy success rates in three groups: two IUIs 12 and 34 hours after hCG; one IUI at 34 hours after hCG; two IUIs 34 and 60 hours after hCG. Patients who had two IUI procedures 12 and 34 hours after the hCG shot had more than twice the pregnancy success rate (30.4%) when compared with women in the other two groups (14.4% and 10.9%).