Different dosage protocols of atosiban in repeated implantation failure before embryo transfer: A double-blind randomized controlled trial

Objective: Atosiban has demonstrated effectiveness in improving pregnancy outcomes in patients with recurrent implantation failure (RIF). However, the optimal dosage protocol is yet to be established, and only a few studies have directly compared different regimens. Materials and methods: This double-blind, randomized controlled trial recruited 100 patients with RIF undergoing treatment at the Assisted Reproductive Technology Center at National Cheng Kung University Hospital between March 2022 and May 2024. Patients were assigned to receive either a bolus protocol of atosiban (6.75 mg; Group A, n = 50) or an infusion protocol of atosiban (total 37.5 mg; Group B, n = 50) before embryo transfer. Results: Although no significant differences were observed, Group B showed a tendency toward higher live birth rates (6.0% vs 20.0%, RR = 3.333; P = 0.071). Other pregnancy outcomes also demonstrated a positive trend, with a notably higher ongoing pregnancy (6.0% vs 20.0%, RR = 3.333; P = 0.071) and a lower miscarriage rate (75.0% vs 33.3%, RR = 0.444; P = 0.054). Subgroup analysis revealed a significant benefit of the infusion protocol in subgroups of patients with high fertility quality of life scores and high-quality embryos (P = 0.039 and 0.048, respectively). Conclusion: The atosiban infusion protocol demonstrated a positive trend in pregnancy outcomes among patients with RIF. Further large-scale studies are needed to confirm its effectiveness and establish optimal strategies.