Publication:

Impact of Atosiban administration on live birth rates in patients undergoing frozen embryo transfer: a retrospective self-controlled study

Background To evaluate the impact of Atosiban, an oxytocin receptor antagonist, on live birth rates (LBR) and other pregnancy outcomes in patients with a history of failed frozen embryo transfer (FET) cycles.

Methods This was a retrospective, self-controlled study conducted at a single tertiary care center between January 2018 and December 2024. A cohort of 73 patients who had undergone at least one unsuccessful FET cycle (Cycle 1) without atosiban and a subsequent FET cycle with Atosiban administration (Cycle 2) were included. Each patient served as her own control. The primary outcome was the live birth rate. Secondary outcomes included biochemical pregnancy, clinical pregnancy, miscarriage, and implantation rates. Statistical analysis involved paired t-tests for continuous variables and Fisher's exact test for categorical outcomes.

Results The administration of Atosiban in Cycle 2 was associated with a significant improvement in pregnancy outcomes. The live birth rate increased from 0% in Cycle 1 to 26.0% in Cycle 2 (p<0.001). Similarly, the clinical pregnancy rate rose from 2.7%-43.8% (p<0.001), and the biochemical pregnancy rate increased from 11.0%-65.8% (p<0.001). The implantation rate showed a non-significant increase from 50% in Cycle 1 to 55% in Cycle 2 (p=0.372).

Conclusions In a self-controlled cohort of patients with previous FET failure, Atosiban administration at the time of embryo transfer was associated with a statistically and clinically significant increase in live birth rates. These findings support Atosiban as a valuable therapeutic option to improve implantation success in this challenging patient population.