Systematic review and meta-analysis of the impact of the refreezing and rebiopsy embryos on reproductive outcomes in patients undergoing freeze-thaw embryo transfer.

Abstract

Objective: To explore whether refreezing and rebiopsy affect reproductive outcomes.

Design: Systematic review and meta-analysis.

Setting: Not applicable.

Intervention(s): Computer search was conducted in PubMed, Embase, Cochrane Library, Web of Science, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, WanFang Data, and VIP Chinese Science and Technology Periodical Database and searched until May 2023. Statistics Data Multi-Processing/Multi-Processor Software was used for conducting data analysis. Dichotomous outcome data were pooled to calculate odds ratios (ORs) and their corresponding 95% confidence intervals (CIs). Continuous outcome data were combined using an inverse variance model to determine the mean difference between the two groups. Random-effects and fixed-effects meta-analysis models were employed to assess heterogeneity. Subgroup analysis was conducted on the basis of different freezing methods and various embryo types.

Main outcome measure(s): The primary outcome measure was the live birth rate (LBR), with secondary indicators including clinical pregnancy rate (CPR), implantation rate, miscarriage rate (MR), ectopic pregnancy, preterm delivery, mean birth weight of neonates, and neonatal malformation.

Result(s): This study included 19 retrospective studies with a total of 11,024 FET cycles. Across the FET cycles, recryopreservation, compared with once-cryopreservation, demonstrated reduced LBRs (OR, 0.79; 95% CI, 0.60-0.92; I² = 21.7%), reduced CPRs (OR, 0.74; 95% CI, 0.60-0.92; I² = 56.9%), and increased MRs (OR, 1.27; 95% CI, 1.03-1.55; I² = 37.1%). Pregnancy outcomes after rebiopsies, revealing significantly lower LBRs after rebiopsies than after single biopsy (OR, 0.65; 95% CI, 0.45-0.94; I² = 43.5%). Similarly, rebiopsies were associated with reduced CPRs (OR, 0.75; 95% CI, 0.54-1.03; I² = 29.6%) and increased MRs (OR, 1.54; 95% CI, 0.89-2.66; I² = 13.0%) compared with single biopsy.

Conclusion(s): Refrozen embryos compared with once-frozen embryos suggest a decrease in the LBRs and CPRs, coupled with an increase in the MRs, with negligible influence on neonatal outcomes. Similarly, rebiopsy yields comparable results, leading to a reduction in the LBRs.