GnRH antagonist ganirelix prevents premature luteinization in IUI cycles: rationale for its use.

This study evaluated the efficacy of a gonadotrophin-releasing hormone antagonist (GnRHa) to prevent premature luteinization (PL) and examined its impact on intrauterine insemination (IUI) cycle outcome. A total of 662 patients who were undergoing IUI were evaluated. Ovarian stimulation was started on day 3 with recombinant (r)FSH, followed by the GnRHa and recombinant human chorionic gonadotrophin (rHCG). The overall incidence of PL was 11.5%. In patients with and without PL, the pregnancy rates (PR) were 22.4 (17/76) and 17.7% (104/586) respectively. Patients with PL were divided into two groups: (i) those with increased serum progesterone [PR was 10.7% (3/28) in this group]; and (ii) patients with elevated serum LH but normal progesterone concentrations [PR was 29.2% (14/48) in this group]. Patients in the first group who did not become pregnant (n = 22) were administered GnRHa in a second IUI cycle, and the PR was 18.1%; however, some patients (n = 6; 27.3%) in this group still had high serum progesterone concentrations. In the second group, patients (n = 26) with elevated serum LH in the previous cycle were administered GnRHa in another IUI and the PR was 23.1%. Use of a GnRHa in patients with PL who have had a previous unsuccessful IUI may be an alternative in future attempts.