Advancing paternal age does not negatively impact fresh embryo transfer cycle outcomes

Research question: What is the impact of advancing paternal age, stratifying for maternal age, on fresh embryo transfer cycle outcomes? Design: All first autologous fresh embryo transfer cycles between 2013 and 2019 at a single high-volume academic institution were retrospectively reviewed. Female age was dichotomized along the cohort median of (37 years) (Female-Young [F-Y]: <37 years; Female-Old [F-O]: >= 37 years). Male age was stratified along the cohort median (38 years) and 90th centile (48 years) (Male-Young [M-Y]: <38 years; Male-Intermediate [M-I]: <= 38 and >48 years; Male-Old [M-O]: >= 48 years). The primary outcome of interest was the odds of live birth using logistic regression. Secondary outcomes included odds of implantation, clinical intrauterine pregnancy and pregnancy loss. All models were adjusted for continuous female age, use of surgically retrieved testicular spermatozoa, severe oligozoospermia and cleavage- versus blastocyst-stage embryo transfer. Results: A total of 6704 couples were included and were divided into six groups based on paternal/maternal age groups (F-Y/M-Y: 2288; F-Y/M-I: 750; F-Y/M-O: 97; F-O/M-Y: 679; F-O/M-I: 2310; F-O/M-O: 580). While some associations were seen on univariable logistic regression, none of the groups with increasing paternal age showed any statistically significant differences on multivariable logistic regression with respect to implantation, clinical intrauterine pregnancy, pregnancy loss or live birth. Conclusions: Advanced paternal age does not impact clinical outcomes in fresh transfer cycles. The authors postulate that IVF with or without intracytoplasmic sperm injection is able to overcome the deleterious effects of advancing paternal age on sperm quality and subsequent embryo performance.