The timing of IUI following ovulation induction has been the subject of many studies and a consensus has developed that a single insemination approximately thirty-six hours after ovulation induction is sufficien. The introduction of GnRH antagonists preventing a premature LH surge and early ovulation has added a new dimension to fertility treatment. It allows greater accuracy in predicting the timing of ovulation and has been shown to be at least as effective, if not more effective, as ovarian stimulation without antagonists. We hypothesize that by utilizing GnRH antagonists we can increase pregnancy rates during IUI by timing the IUI as close as possible to the moment of ovulation guaranteeing the highest and freshest concentration of motile spermatozoa in the fallopian tube at the time the oocyte is released from the ovary. We therefore propose a randomized open three arm prospective trial utilizing superovulation with GnRH antagonists whereby the IUI is timed to take place 36, 42 or 48 hours after ovulation induction.