Dados do Trabalho

Title

Aneuploidy for chromosomes 13,18,21, X and Y in blastocysts from ICSI/PGT-A cycles.

Objective

The aim of this study was to analyze the aneuploidy for chromosomes 13, 18, 21, X and Y in embryos from couples undergoing ART (Assisted reproduction techniques) with ICSI (Intracytoplasmic Sperm Injection) and preimplantation genetic test (PGT-A)

Methods

This observational retrospective cohort study included 206 patients that performed IVF cycle in combination with preimplantation genetic test for Aneuploidy (PGT-A) at IVI (Valencian Institute of Infertility) Salvador from January 2022 to December 2022. A total of 461 embryos obtained from this cycles were biopsied and vitrified. Embryo biopsies were performed at blastocyst stage (day 5/ 6). All chromosomes of the embryos were analyzed with next generation sequencing technology (NGS).

Results

The mean age of the patients was 38,7 years and the average number of embryos analyzed per cycle was 2.23. A total of 195 (42,3%) blastocysts resulted euploid and 266 (57,7%) were aneuploid, due to monosomy, trisomy, mosaic and complex abnormalities. Of the total number of embryos analyzed, 9 (1,95%) embryos had a result of Trisomy 21, 6 (1,3%) presented Trisomy 18, and 1 (0,21%) were defined as Trisomy 13. Turner (monosomy X) and Klinefelter (disomy X) were not found among the analyzed embryos. Evaluating the chromosomal aneuploidy, maternal age and cause of infertility, we reported that among the embryos presenting Trisomy 21, 5 were from patients aged ≤ 37 years and cause of infertility associated with male factor, and 4 embryos were from women ≥ 37 years and cause of infertility advanced maternal age. The 6 embryos that presented Trisomy 18 were from women aged ≥ 37 years and the cause of infertility associated with maternal age in 5 of them and only 1 was related to both advanced maternal age and male factor. The embryo that presented Trisomy 13 resulted from a 36-year-old patient with male factor infertility.

Conclusion

Different factors, such as advanced maternal age, male factor, recurrent miscarriages can affect the success of pregnancy and live births in couples around the world. With PGT-A chromosomal changes may be detected prior to embryo transfer and increase the chances of a successful pregnancy by cycle, transferring an euploidy embryo. With few exceptions, aneuploidies do not appear to be compatible with life. In fact, about 35% of spontaneous abortions are caused by trisomies. Studies show that trisomies can arise from errors of segregation in either parent and any meiotic division. The main numerical chromosomal alterations found in live births are associated with chromosomes 13, 18, 21, X and Y. Of the findings in this study, few aneuploidy embryos had trisomy 13, 18 and 21 and no aneuploidies associated with sex chromosomes were found. Several authors have questioned the practice of PGT-A, however new studies should intensify investigations about genomic medicine associated with assisted human reproduction techniques to expand knowledge in search of better results for couples who undergo IVF treatments.

Keywords

Aneuploidy, Preimplantation Genetic Test, Chromosome, Intracytoplasmic Sperm Injection.