Pituitary block with gonadotrophin-releasing hormone antagonist during intrauterine insemination cycles: a systematic review and meta-analysis of randomised controlled trials

Background: Several randomised controlled trials (RCTs) have investigated the usefulness of pituitary block with gonadotrophin-releasing hormone (GnRH) antagonists during intrauterine insemination (IUI) cycles, with conflicting results. Objective: The aim of the present systematic review and meta-analysis of RCTs was to evaluate the effectiveness of GnRH antagonist administration as an intervention to improve the success of IUI cycles. Search strategy: Electronic databases (MEDLINE, Scopus, EMBASE, Sciencedirect) and clinical registers were searched from their inception until October 2017. Selection criteria: Randomised controlled trials of infertile women undergoing one or more IUI stimulated cycles with GnRH antagonists compared with a control group. Data collection and analysis: The primary outcomes were ongoing pregnancy/live birth rate (OPR/LBR) and clinical pregnancy rate (CPR). Pooled results were expressed as odds ratio (OR) or mean differences with 95% confidence interval (95% CI). Sources of heterogeneity were investigated through sensitivity and subgroups analysis. The body of evidence was rated using GRADE methodology. Publication bias was assessed with funnel plot, Begg's and Egger's tests. Main results: Fifteen RCTs were included (3253 IUI cycles, 2345 participants). No differences in OPR/LBR (OR 1.14, 95% CI 0.82–1.57, P = 0.44) and CPR (OR 1.28, 95% CI 0.97–1.69, P = 0.08) were found. Sensitivity and subgroup analyses did not provide statistical changes in pooled results. The body of evidence was rated as low (GRADE 2/4). No publication bias was detected. Conclusion: Pituitary block with GnRH antagonists does not improve OPR/LBR and CPR in women undergoing IUI cycles. Tweetable abstract: Pituitary block with GnRH antagonists does not improve the success of IUI cycles.