Abstract
PURPOSE: To evaluate the effectiveness and safety of personalized embryo transfer (pET) guided by TERTs compared with standard embryo transfer (sET) in assisted reproductive technology. METHODS: Systematic review and meta-analysis of randomized controlled trials (RCTs) and cohort studies (CS) at low or moderate risk of bias was conducted. PubMed/MEDLINE, EMBASE, CENTRAL, LILACS, and CINAHL were searched to November 2025 without restrictions. Conference abstracts and reference lists were also screened. Reviewers independently screened, extracted data, and assessed risk of bias. RCTs and CS were pooled separately using random-effects models. Odds ratios (ORs) were synthesized using the generic inverse-variance method. Prespecified subgroups included prior failures and euploid transfers. RESULTS: We included 44 studies (4 RCTs; 40 CS). Thirty-five studies evaluated ERA, six rsERT, and four other platforms. In women with limited or no prior failures, two low-risk RCTs showed pET with ERA probably results in little or no difference in LBR versus sET (RR 0.98, 95% CI 0.88-1.10; 1069 women; moderate certainty). In women with recurrent implantation failure (RIF) transferring untested embryos, nine low/moderate-risk CS showed a probable increase in LBR with TERT-guided pET (OR 1.58, 95% CI 1.34-1.86; 4754 women; moderate certainty), with similar direction of effect across ERA, rsERT, and ERT. Among RIF women undergoing euploid transfers, five studies provided very uncertain evidence of benefit (OR 1.36, 95% CI 0.83-2.22; 852 women; very low certainty). Findings were heterogeneous and imprecise, yielding very low certainty of evidence. CONCLUSION: Current evidence does not support routine use of TERTs in non-RIF. In RIF, TERT-guided pET is probably associated with higher LBR when untested embryos are transferred, but benefits remain uncertain in euploid transfers, reflecting either a small biological effect, methodological bias, or inconsistent protocol implementation. Future research should prioritize adequately powered RCTs in RIF, especially with euploid embryos, and direct comparisons of TERT platforms and assessment of test reproducibility.