The effect of intrauterine human chorionic gonadotropin flushing on live birth rate after vitrified-warmed embryo transfer in programmed cycles: a randomized clinical trial.

Purpose: To assess the influence of intrauterine human chorionic gonadotropin (hCG) before embryo transfer on the clinical pregnancy and live birth rates after vitrified-warmed embryo transfer (ET) in programmed cycles.

Methods: This study was a single-blind randomized clinical trial for eligible patients underwent frozen ET cycles with long-term hormonal GnRH agonist protocol for endometrial preparation. Immediately prior to ET, the women were randomly divided into three groups. In the experimental group, 7-10 min before embryo transfer, 500 IU of hCG with a 40 μL of culture medium was injected into the uterus. In the first control (sham) group, 7-10 min before ET just 40 μL of culture medium intrauterine was infused. In the second control group, no intervention was done. The pregnancy outcomes were compared in the three groups using appropriate statistical tests.

Results: Finally, 180 patients allocated into three groups. There was no significant difference in terms of patients 'characteristics among three groups. No significant difference was found in terms of clinical pregnancy among three groups. The miscarriage rate in control group (0%) was significantly lower than those of in the sham and hCG groups (9.8% and P = 0.01, 6.6% and P = 0.04, respectively). In addition, live birth rate (39.3%) in control group was significantly higher than those of in the sham and hCG groups (16.4% and P = 0.005, 23% and P = 0.051, respectively).

Conclusion(s): It was found that intrauterine injection of 500 IU hCG before vitrified-warmed ET at cleavage stage has no beneficial effect on pregnancy outcome and is not suggested. NCT02355925.