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

In the 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.

The findings indicated that male age 40 years or older was associated with significantly reduced LBRs in IVF cycles for female partners aged 35 to 39 years. Compared with male partners younger than 35 years who had an LBR of 27.0%, rates declined to 22.9% in men aged 40 to 44 years and to 18.8% in men older than 50 years. This decline persisted irrespective of male infertility status. However, no significant impact of male age was observed in women younger than 35 years or older than 40 years.

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.

The study 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 years, particularly when female partners were younger than 40 years, though statistical significance was limited. The investigators noted that these trends should be interpreted with caution as a result of the study's retrospective design and the absence of data on cumulative live birth rates from frozen-thawed embryo transfers.

The results demonstrated the interaction between male and female partner age on IVF outcomes and indicated that ICSI may mitigate age-related effects of sperm in older male partners, even without male factor infertility. However, additional studies are needed to confirm these therapeutic implications.

Full disclosures can be found in the published study.