Ovulation induction with gonadotropin-releasing hormone

Perhaps 20% to 25% of infertility may result from the failure to ovulate regularly. Despite the many causes of ovulatory dysfunction (Table 1), until recently, with the introduction of gonadotropin-releasing hormone (GnRH), only three different medications have been available to treat these disorders successfully. These drugs are human menopausal gonadotropin (hMG), bromocriptine, and clomiphene citrate (CC). The discovery of GnRH in 1971 offered anovulatory patients a physiologic medication to be used in their treatment. It was felt that GnRH would eventually supplant other forms of therapy. When GnRH was initially used the results were disappointing, but it now appears that GnRH therapy may well fulfill its promised role. This review will describe the biochemistry of GnRH, past and present protocols of GnRH administration to induce ovulation, and side effects.