Men may feel younger than their age, but their sperm isn’t fooled. Increasing age in men is associated with a number of significantly worse reproductive outcomes, according to several studies presented at the American Society for Reproductive Medicine annual meeting.
Older age has a negative impact on sperm DNA, embryo formation, and live-birth rates, these studies showed.
Reproductive Medicine Associates, Morristown, and Medical School, New Brunswick, NJ, reported a study involving older men and anonymous young egg donors.
Increasing maternal age adversely impacts fertility, but little intention has been paid to male age.
The study was a retrospective cohort analysis of 1023 oocyte donation cycles in couples seeking assisted reproduction. Male partners (mean age, 42 years) were stratified into five-year age categories. Mean donor age was 41.
Increasing age was associated with a trend for worse sperm parameters, including concentration, morphology, and motility. Blastocyst development on Day 5 (optimal time for implementation) was significantly reduced as the male cohort aged. For men ≤ 50, this point was reached by 41% compared with only 34% for those older than 50.
Outcome rates, which included implantation, pregnancy, loss, and live births, showed a significant disadvantage for the older men.
The sperm’s ability to penetrate the egg, and the resulting early embryos, do not seem to be altered significantly by aging of sperm; however, later embryo development, after the cleavage stage, is significantly affected, leading to a significant decrease in blastocyst formation rate and a tremendous increase in pregnancy loss after age 50.
Another study involving 1025 oocyte donation cycles showed that effects of advanced male age may be responsible for lower pregnancy rates in advanced maternal age egg donation recipients. The pregnancy rate for couples with male partners > 50 years was 61% compared with 72% for male partner’s ≤ 39 years. Maternal age did not affect outcomes, reported by the German Hospital, Istanbul, Turkey.
Sperm decline may begin at 35
In another study of 56 semen samples of men undergoing in vitro fertilization, the rate of DNA fragmentation of sperm was significantly higher for patients aged ≥ 35 years.
Male factor infertility patients can have abnormalities of sperm nuclei or display high levels of loosely packed chromatin and damaged DNA.
Sperm genome quality has been known for several years to play a major role in early embryogenesis, and thus in outcomes from assisted reproductive technology. This study evaluated nuclear DNA fragmentation in sperm in relation to age. The rate of DNA fragmented sperm was reported as the DNA fragmentation index (DFI), which showed the mean percent of sperm in a sample with abnormal DNA.
Men aged 30 to 35 years had a DFI of 14.33% for men aged ≥ 36 years (P<.05), although not statistically significant, there were similar numerical differences for sperm concentration, motility, and morphology. Since the oldest man in the study was 47 years, older age-groups could not be evaluated.
After analyzing the rates of DNA-fragmented sperm in detail, they determined that the border of significance is the age of 35. They concluded that patients aged 36 or older have a lower chance of successful outcomes with assisted reproductive technology. In their opinion, the age of 35 really marks a border between good and bad sperm, the doctor of Reprogen-Ulm, Ulm, Germany said.