Impact of repeated vitrification and biopsy on the developmental potential of blastocysts and clinical outcomes: A retrospective propensity-score-matched cohort study.

Purpose: This study aimed to investigate the effects of repeated vitrification and trophectoderm (TE) biopsy procedures during preimplantation genetic testing (PGT) on blastocyst developmental potential and clinical outcomes.

Methods: This retrospective study analyzed data from January 2018 to January 2024. The study group included 229 blastocysts from 85 patients that underwent double vitrification (with either single or double biopsy). The control group consisted of 2,611 embryos from 654 patients who underwent conventional PGT with a single vitrification. Propensity score matching (PSM) in a 1:2 ratio was employed to balanced baseline characteristics. The primary outcome was live birth rate, with secondary outcomes including ploidy status, implantation, and miscarriage rates.

Results: After PSM, the double-vitrification group (226 blastocysts) was compared to a matched single-vitrification group (719 blastocysts). The double-vitrification group exhibited a significantly lower live birth rate (32.61% vs. 54.87%, p = 0.011). For embryos biopsied on Day 5, the double-vitrified group showed a significantly lower euploidy rate (37.80% vs. 48.79%, p = 0.032). A subgroup analysis within the double-vitrification group found no significant differences in ploidy status, clinical pregnancy rates, or live birth rates between embryos that underwent a single biopsy versus those that underwent a double biopsy (p > 0.05).

Conclusion: Repeated vitrification negatively impacts clinical outcomes in PGT cycles, specifically by reducing the live birth rate. However, the frequency of biopsy (single vs. double) does not appear to significantly affect clinical success. These findings suggest that while re-biopsy is a viable option for inconclusive cases, caution should be exercised regarding repeated vitrification procedures.