Timing of intrauterine insemination: where are we?

Correct timing of insemination remains a controversial aspect of IUI cycles associated with ovarian hyperstimulation. Although it is currently believed that insemination at 32–38 hours after hCG administration provides the best results, clinical evidence supporting this conclusion is scarce. Double insemination might be an alternative, effective strategy, but studies on this topic are few, heterogeneous, and controversial.