['To determine whether endometrial hCG infusion at the time of human blastocyst transfer impacts implantation rates.', 'Randomized double-blinded placebo-controlled trial.', 'Academic.', 'Infertile couples with the female partner less than 43 years old (n = 300) undergoing fresh or frozen ET of one or two blastocysts.', 'Patients undergoing ET were randomized into either a treatment or a control group. The treatment group received an infusion of 500 IU of hCG diluted in ET media. The control group received a sham infusion of ET media. Infusions were done using a separate catheter less than 3 minutes before actual ET.', 'Sustained implantation rate: ongoing viable gestation (primary outcome) and ongoing pregnancy rate (secondary outcome).', 'A total of 473 blastocysts were transferred into 300 patients. There were no differences between the two groups in sustained implantation rate (48.1% in the hCG group, 44.2% in the control group) or ongoing pregnancy rate (58.8% in the hCG group, 52.0% in the control group).'] Does endometrial infusion of human chorionic gonadotropin at the time of blastocyst embryo transfer impact clinical outcomes : a randomized , double-blind , placebo-controlled trial?