Antagonist use in intrauterine insemination (IUI) cycles.

Intrauterine insemination is the first method of treatment for many causes of infertility, mainly unexplained infertility, male subfertility, and ovulatory dysfunction. Despite its popularity, the effectiveness of IUI treatment is not consistent, and the role of IUI treatment in practice protocols has not been clarified. The success of IUI depends on a number of parameters linked both to the pathology underlying the infertility and to the treatment. The midcycle LH surge in the reproductive cycle is an intriguing endocrinological phenomenon. One of the challenges to optimize the COS/IUI outcomes is to prevent the occurrence of the premature LH rise and consequent luteinization.24% of IUI cycles suffer from premature LH surge. The potential beneficial effect of a GnRH antagonist on pregnancy rates in IUI cycles, while preventing premature LH surge, has not been adequately assessed. Administration of a GnRH antagonist almost completely abolishes premature luteinization but does not substantially improve the pregnancy rate. Co-treatment with GnRH antagonists can be restricted to the time in the cycle where there is a risk of a premature increase in LH.