F2 and antiphospholipid syndrome: As a non-criteria antiphospholipid syndrome antibody, anti-phosphatidylserine/prothrombin antibodies were investigated in this study to explore their effects on oocyte quality and pregnancy outcomes in patients with unexplained recurrent implantation failure.<h4>Methods</h4>This was a retrospective cohort study that included 853 IVF/ICSI cycles from patients with URIF at Peking University Third Hospital between April 2021 and April 2023, with patients stratified into positive and negative groups for anti-phosphatidylserine/prothrombin antibodies.