JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):150
Poster Presentation
29^th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263939

P-138. Impact of Paternal Age on Embryo Development Rate on Day 5

Layana Freitas Souza¹, Darlete Lima Matos¹, Karla Rejane Oliveira Cavalcanti¹, Fabricio Sousa Martins¹, Ilania Kaline Oliveira da Rocha¹, Daniel Paes Diogenes de Paula¹, Lilian Maria da Cunha Sério¹

¹ Fertibaby Ceará – Fortaleza - CE - Brasil

Objective: The main objective of this study is to investigate the influence of paternal age on the blastocyst formation rate on the fifth day of development (D5) in in vitro fertilization (IVF) cycles. The research aims to understand whether male aging is associated with changes in embryonic developmental potential, assessing a possible reduction in embryo formation up to the blastocyst stage—a phase considered crucial for embryo implantation and reproductive treatment success.
Methods: This is a retrospective study based on the analysis of clinical data collected between 2020 and 2025, involving a total of 145 embryos from patients undergoing IVF cycles at an assisted reproduction center. All embryos included in this study were generated using the intracytoplasmic sperm injection (ICSI) technique. Embryos were monitored from the moment of fertilization until the fifth day of development, at which point blastocyst formation was assessed. The data were organized into three distinct groups according to paternal age: group 1, under 40 years old; group 2, between 41 and 49 years old; and group 3, 50 years or older. For each group, the embryo development rate was calculated based on the proportion of embryos that reached the blastocyst stage. A comparative descriptive analysis was conducted, presenting absolute frequencies (number of embryos that reached the blastocyst stage in each group) and relative frequencies (percentage relative to the total number of embryos analyzed in each age group). No inferential statistical tests were applied, and the conclusions were based on the observed proportional differences between the evaluated groups.
Results: Of the 145 embryos analyzed, 79 (54.48%) reached the blastocyst stage on the fifth day of development. When segmenting the data by paternal age group, the blastocyst rate was highest in the group under 40 years old (65.96%). In the 41 to 49-year-old group, the rate was 60.42%. In the group aged 50 years or older, the embryo development rate dropped to 38.00%. The difference observed between groups, especially between the youngest and oldest age ranges, suggests a trend of decreasing embryo development rate associated with increasing paternal age. Maternal age and the quality of female gametes were previously controlled to reduce potential biases in interpreting the results, allowing a more direct assessment of the impact of the male partner's age.
Conclusion: The findings of this study suggest that advanced paternal age may negatively affect the embryonic development rate in IVF cycles, particularly regarding blastocyst formation on the fifth day. The significant reduction observed in patients aged 50 or older reinforces the importance of considering the male partner's age as a relevant factor in reproductive planning and clinical strategies. These results have important implications in the field of reproductive medicine, highlighting the need to include the male partner's age in counseling couples seeking treatment. Additionally, it underscores the importance of future research exploring the molecular and cellular mechanisms associated with male aging and sperm quality.