Spontaneous Triggering of Ovulation vs. Administration of Human Chorionic Gonadotropin in Patients Undergoing Intrauterine Insemination: a Prospective Randomized Study.

We recently reported the superiority of the natural cycle to a natural cycle controlled by the administration of human chorionic gonadotropin (hCG) for planning the frozen-thawed embryo transfer cycles, demonstrating a probable negative impact of exogenous hCG on endometrial receptivity.Based on the above findings we conducted the first prospective study that assesses whether there is a difference in pregnancy rate after intrauterine insemination (IUI) in a natural cycle with spontaneous luteinizing hormone (LH) rise compared to natural cycles controlled by hCG for final ovulation.