JBRA Assist. Reprod. 2025;29(Suppl 1):40-40
POSTER PRESENTATION
doi: 10.5935/1518-0557.20250094
P-026. Analysis of the Sex Ratio in Human Embryos According to Assisted Reproduction Techniques
1Institute of Reproductive Medicine Ricardo Palma Clinic. Lima, Perú
Objective: To evaluate the distribution of chromosomal sexes among human embryos in relation to the insemination technique, day of embryo culture, blastocyst quality, and chromosomal status.
Methods: A retrospective cohort study was conducted involving 589 IVF/ICSI cycles, utilizing both donated and self-provided eggs, with preimplantation genetic screening carried out at Clínica Ricardo Palma - Instituto de Medicina Reproductiva between January 2023 and February 2025. Biopsies from 2004 embryos on days 5, 6, and 7 were analyzed using Next-Generation Sequencing (NGS), which determined the chromosomal status of each embryo (euploid, mosaic, and aneuploid). Additionally, blastocysts were assessed using Gardner’s criteria and categorized as good (AA, AB, BA), fair (BB, BC, CB), and poor (AC, CA, CC). Statistical analyses were conducted using a chi-square test (χ2) to determine if there were statistically significant differences in the sex ratio of XX and XY; p<0.05.
Results: The average age of the patients was 38± 4 years. Analysis revealed no significant differences in the chromosomal distribution (XX vs. XY) of embryos across different culture days (p=0.269); additionally, no significant differences were confirmed with a specific-day analysis (p>0.5). Furthermore, no significant differences were detected in the sex ratios between conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) techniques (p=0.228), even when analyzed separately. The distribution of XX and XY chromosomes also showed no significant differences in relation to embryo quality (p=0.111), in both overall analyses and category-specific evaluations. However, a significant prevalence of XX embryos was observed in the mosaic embryo category (p=0.017), suggesting that chromosomal status may influence sex distribution. In contrast, euploid and aneuploid embryos showed no significant differences (p=0.069).
Conclusion: The present study demonstrated that the chromosomal sex distribution (XX and XY) remains balanced in embryos derived from IVF and ICSI, as well as throughout culture days 5, 6, and 7. Embryo quality, assessed and categorized using Gardner’s criteria, showed no influence on the sex ratio. However, a significant prevalence of XX embryos was observed in mosaic embryos, underscoring the potential impact of chromosomal alterations on sex distribution. Further studies are recommended to explore this association.
Table 1. Distribution of Chromosomal Sexes in Embryos by Culture Day, Fertilization Technique, Embryo Quality, and Chromosomal Status.