Treatment randomization and blinding
Eligible patients were randomly assigned to the AST or placebo groups (1:1) using the balanced block randomization method within a block size of 4 by an independent statistician. This trial was a triple-blind study. All patients, researchers, statisticians, embryologists, and laboratory personnel were blinded to the individual treatment allocation. The Consolidated Standards of Reporting Trials (CONSORT) diagram (Patient enrolment and CONSORT diagram.