JBRA Assist. Reprod. 2025;29(Suppl 1):11-11
ORAL PRESENTATION
doi: 10.5935/1518-0557.20250068
1GERMINAR Fertility Center, Lima-Perú
2CLINIFER Fertility Center, Chiclayo-Perú
3Fertility Center of Cajamarca, Cajamarca-Perú
4Igenomix Perú
Objective: To determine whether the mechanical-only embryo biopsy technique alters euploidy and chromosomal abnormalities compared to the conventional laser-assisted technique in preimplantation genetic testing for aneuploidies (PGT-A) in own and donated eggs.
Methods: A retrospective study analyzed a total of 816 embryo biopsies performed by the same team of embryologists across three centers in Perú. Two of the labs performed mechanical-only biopsies (234), while the third lab used a conventional biopsy technique (582). The samples were divided into two groups: Own eggs (OE) (n=462; 337 by conventional and 125 by mechanical-only biopsies) and donated eggs (DE) (n=354; 245 by conventional and 109 by mechanical-only biopsies). All embryos underwent trophectoderm biopsies on days 5 or 6 of development. In the conventional biopsy group, embryos underwent laser-assisted hatching (AH) on day 4, followed by biopsy at the blastocyst stage using laser-assisted flicking or pulling. In the mechanical-only group, blastocysts on day 5/6 underwent AH by exposing the zona pellucida opposite the inner cell mass to acid Tyrode’s released through an ICSI pipette, and cultured for 5-7 hours before biopsy using the flicking technique, without laser assistance. All samples were analyzed using smart PGT-A by Igenomix.
Results: The overall sex distribution showed no significant difference, with females representing 49.0% and males 51.0% in the conventional biopsy group, compared to 48.0% females and 52.0% males in the mechanical-only group (p=0.7). In OE group was no statistically significant difference in the euploidy rates between the conventional (43.0%) and mechanical-only (46.0%) groups (p=0.7). Additionally, the percentages of informative samples (99.7% vs. 100.0%) and mosaicism (5.9% vs. 7.2%) were similar between the two groups (p>0.05), and the rates of monosomy (27.0% vs. 31.0%), trisomy (22.0% vs. 22.0%), segmental alterations (6.8% vs. 4.0%), complex alterations (23.0% vs. 26.0%), and chaotic alterations (0.9% vs. 0.0%) were also comparable between the conventional and mechanical-only groups respectively (p>0.05). In DE group was no statistically significant difference in the euploidy rates between the conventional (70.0%) and mechanical-only (69.0%) groups (p=0.9). Additionally, the percentages of informative samples (99.2% vs. 100.0%) and mosaicism (5.3% vs. 5.5%) were similar between the two groups (p>0.05), and the rates of monosomy (9.0% vs. 13.0%), trisomy (6.9% vs. 6.4%), segmental alterations (9.4% vs. 4.6%), complex alterations (6.9% vs. 11.0%), and chaotic alterations (2.4% vs. 0.0%) were also comparable between the conventional and mechanical-only groups respectively (p>0.05).
Conclusion: Our results suggest that the mechanical-only biopsy technique has no significant impact on euploidy or chromosomal abnormalities in both own and donated eggs, making it a reliable option when expensive laser technology is unavailable, as is the case in many laboratories in Latin America. Despite the promising results, the study's main limitations include its retrospective design and the smaller sample size in the mechanical-only group. Therefore, larger, prospective studies are needed to validate these findings.