ABSTRACT
Introduction: To evaluate the efficacy of GnRH antagonists in terms of increasing the pregnancy rates in intrauterine insemination (IUI) after controlled ovarian stimulation (COS) when more than one dominant follicle is recruited. Methods: This is a prospective and randomized clinical trial that included 300 couples with primary or secondary infertility that underwent their first or second COS-IUI cycle with recombinant FSH. In all of these patients two or three leading follicles > 14 mm of mean diameter where detected by vaginal ultrasound (US) and were randomized into two groups. In group A the patients received rFSH+GnRH antagonists until the day that the hCG was given, while in group B the patients followed a standard COS received rFSH only. Results: Total amount of rFSH units (620.8+245.1vs 575.5+296.4) and clinical pregnancy rates (31.16% vs 19.15%) were statistically significantly higher in patients who were treated with GnRH antagonists. A similar number of twin pregnancies and miscarriages occurred in both groups. Conclusion: Multiple doses of GnRH antagonists in COS-IUI significantly increase pregnancy rates in multifollicular cycles.