Effects and clinical significance of GnRH antagonist administration for IUI timing in FSH superovulated cycles: a meta-analysis

Objectives To compare the administration of GnRH antagonist in gonadotropin intrauterine insemination (IUI) cycles with cycles where no intervention took place. Design Meta-analysis of published prospective randomized trials. Patients(s) Five hundred twenty-one patients who were administered a GnRH antagonist and 548 conservatively treated patients who served as control subjects were included in the meta-analysis. Intervention(s) Study selection: Prospective trials were retrieved from Medline and Cochrane Library (last update October 2006). Random effect analysis was used in this meta-analysis. Two independent reviewers performed data extraction. Main Outcome Measure(s) Clinical pregnancy rates. Result(s) Six comparisons were retrieved including 1,069 patients. Higher pregnancy rates were found in the randomized controlled trials (odds ratio [OR] 1.56, 95% confidence interval [CI] 1.05–2.33) when a GnRH antagonist was added to a gonadotropin superovulated IUI protocol. Early published studies with smaller sample sizes showed stronger associations (OR 2.31, 95% CI 1.15–4.63) than later studies (OR 1.32, 95% CI 0.79–2.23). Conclusion(s) From the randomized controlled trials of this meta-analysis, it is clear that allowing for follicle growth and avoiding premature LH rise, increased pregnancy rates are observed with GnRH antagonist administration. A parallel trend for multiple pregnancy rates in the GnRH antagonist group was observed, although this did not reach statistical significance. The flexible regimen was widely used. This meta-analysis of early data might enhance further research in this direction.