Males aged 40 years or older significantly reduced live birth rates for vitro fertilization cycles when female partners were aged 35 to 39, but not in younger or older female age groups.

In a retrospective analysis of 59,951 fresh in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles, published in Human Reproduction, investigators explored the effect of male partner age on live birth rates (LBRs) while accounting for female partner age. The study utilized data from the 2017 to 2018 UK Human Fertilisation and Embryology Authority.

Compared with male partners younger than 35 years with an LBR of 27%, rates declined to 22.9% in men aged 40 to 44, and to 18.8% in men older than 50. This decline persisted irrespective of male infertility status. However, no significant impact of male age was observed in women younger than 35 or older than 40.

ICSI cycles showed no significant association between male age and LBRs, indicating a possible association between ICSI use and mitigation of age-related sperm effects. Subgroup analyses, including first treatment cycles and single blastocyst transfers, confirmed these patterns.

Researchers hypothesized that younger female partners (< 35 years) may repair sperm DNA damage through oocyte-mediated mechanisms, though further research is needed to confirm these pathways. Among older female partners (≥ 40 years), diminished oocyte quality may overshadow the impact of sperm aging.

Miscarriage rates trended higher in male partners older than 55, particularly when female partners were younger than 40, though statistical significance was limited. The investigators noted that these trends should be interpreted cautiously because birth rates from frozen-thawed embryo transfers.

Additional studies are needed to confirm these therapeutic implications. Research disclosures can be found in the published study.