Volovsky M, et al. - Here, researchers investigate the factors that affect the outcome of intrauterine human chorionic gonadotropin (hCG) infusion at the time of embryo transfer (ET), specifically, the impact of hCG infusions on fresh and frozen embryo transfers (FETs) and whether prior recurrent implantation failure (RIF) impacts upon outcomes. Intrauterine hCG at the time of ET not only appears to have no benefit but rather a negative impact in fresh ETs and those without RIF.