Serum oxytocin profiles in patients with repeated implantation failure during IVF cycles

Objective: The objective of this study is to investigate the association between oxytocin (OT) levels and repeated implantation failure (RIF) during in vitro fertilization-embryo transfer (IVF-ET) cycles. Methods: Blood samples were collected from 108 women undergoing IVF-ET treatment at the following time points: gonadotrophin (Gn) administration day (Gn Day 0), hCG administration day (hCG Day 0), ET administration day (ET Day 0), and 5 d after ET (ET Day 5). Serum OT and steroid profiles were measured and compared among three groups: Group A included 38 women with a history of RIF, Group B included 41 women who became pregnant following the first fresh ET, and Group C included 29 women who did not become pregnant following the first fresh ET. Results: The OT levels of the three groups at different time points were not significantly different. Serum OT levels were significantly higher on hCG Day 0, ET Day 0, and ET Day 5 than on Gn Day 0, and they were significantly correlated with the estradiol concentration on ET Day 0. Conclusions: RIF patients do not have elevated serum OT levels during IVF-ET cycles.