The effect of intrauterine HCG injection on IVF outcome: a systematic review and meta-analysis

In this systematic review and meta-analysis, the effect of intrauterine HCG infusion before embryo transfer on IVF outcomes (live birth rate, clinical pregnancy rate and spontaneous aboretion rate) was investigated. Searches were conducted on MEDLINE, EMBASE and The Cochrane Library. Randomized studies in women undergoing IVF and intracytoplasmic sperm injection comparing intrauterine HCG administration at embryo transfer compared with no intrauterine HCG were eligible for inclusion. Eight randomized controlled trials were eligible for inclusion in the meta-analysis. A total of 3087 women undergoing IVF and intracytoplasmic sperm injection cycles were enrolled (intrauterine HCG group: n = 1614; control group: n = 1473). No significant difference was found in the live birth rate (RR 1.13; 95% CI 0.84 to 1.53) and spontaneous abortion rate (RR 1.00, 95% CI 0.74 to 1.34) between women who received intrauterine HCG and those who did not receive HCG. Although this review was extensive and included randomized controlled trials, no significant heterogeneity was found, and the overall included numbers are relatively small. In conclusion the current evidence does not support the use of intrauterine HCG administration before embryo transfer. Well-designed multicentre trials are needed to provide robust evidence.