Should intrauterine human chorionic gonadotropin infusions ever be used prior to embryo transfer?

The aim of this study was to explore the factors that influence the outcome of intrauterine human chorionic gonadotropin (hCG) infusion at the time of embryo transfer (ET), in particular, the effect of hCG infusions on fresh and frozen embryo transfers (FETs) and whether prior recurrent implantation failure (RIF) impacts upon outcomes. This was a case-control study based on a standardized database from a multi-site in vitro fertilization clinic. The analysis contains 458 cases and 749 matched controls, with an intervention group of those given intrauterine hCG prior to ET and a control group of patients receiving no hCG infusion. Outcomes were defined as clinical pregnancy and live birth rates. Two analyses were performed. The first separated FETs (cases n = 224, controls n = 325) and fresh ETs (cases n = 234, controls n = 424), with outcomes calculated in each group. The second analysis divided patients into those with RIF (cases n = 149, controls n = 200) and those without (cases n = 309, controls n = 549). Results in fresh ETs demonstrated a 5.8% reduction (adjusted odds ratio (AOR) = 0.60, p = 0.041) in clinical pregnancy rates with the use of intrauterine hCG. In those without defined RIF, clinical pregnancy rates were reduced by 8.1% (AOR = 0.61, p = 0.023) and live birth rates by 7.2% (AOR = 0.56, p = 0.32) with intrauterine hCG use. There were no significant differences in outcomes in FETs and in the RIF cohort. Intrauterine hCG at the time of ET not only seems to have no benefit, but rather a negative effect in fresh ETs and those without RIF.