Intrauterine Administration of Human Chorionic Gonadotropin Improves the Live Birth Rates of Patients with Repeated Implantation Failure in Frozen-Thawed Blastocyst Transfer Cycles by Increasing the Percentage of Peripheral Regulatory T Cells

Repeated implantation failure (RIF) frustrates both patients and their clinicians. Our aim was to observe the effects of intrauterine administration of human chorionic gonadotropin (hCG) on pregnancy outcomes of patients who received frozen-thawed embryo transfer (FET).