The influence of male age and sperm parameters on blastulation and euploidy rates.

Objective: To study the impact of male age and sperm parameters on blastulation and euploidy rates.

Design: Cohort study conducted between July 2017 and August 2023.

Subjects: A total of 47,502 metaphase II oocytes from 5,847 cycles performed with fresh and frozen ejaculated and testicular sperm.

Exposure: Preimplantation genetic testing for aneuploidy from trophectoderm biopsies on day 5-7 culture.

Main Outcome Measures: Association between male-related factors and conditions on reproductive outcomes and euploidy rates. Male factors examined included paternal age, sperm origin (testicular vs. ejaculate), and sperm parameters such as concentration, motility, and morphology, as well as the use of fresh vs. frozen sperm samples. Maternal age was included as a confounding variable and controlled for in the analysis to isolate the impact of paternal factors on the outcomes of interest.

Results: A total of 47,502 mature oocytes from 5,847 cycles were included in the analysis. Multivariable regression analysis showed that lower sperm concentration (0 to <1 million/mL vs. ≥16 million/mL) and testicular sperm use were significantly associated with lower rates of fertilization, euploidy per biopsied blastocyst, and euploidy per metaphase II oocyte. Moreover, lower sperm motility (≤25% vs. >50% to ≤75%) was significantly associated with lower fertilization rates and blastocysts per 2 pronuclei. Frozen sperm and male age had a significant negative association with euploidy per tested blastocyst. In women aged <35 years, increasing male partner age was significantly associated with lower euploidy per tested blastocyst (58.5% ± 31.4, 52.7% ± 34.2, 49.1% ± 35.8, and 51.6% ± 28.7 for male ages of ≤30, >30 to ≤40, >40 to ≤50, and >50 to ≤60 years, respectively). This effect remained significant in the multivariable analysis adjusting for sperm origin, morphology, motility, and sperm concentration for male age categories >30 to ≤40 and >40 to ≤50 years when compared with ≤30 years (risk ratios, 0.96 [95% confidence interval, 0.92-0.99] and 0.92 (95% confidence interval, 0.96-0.99]).

Conclusion: Paternal age impacts blastocyst euploidy rates, whereas sperm factors and conditions exert an impact on fertilization, blastulation, and/or euploidy rates.