Male Aging Linked to Decreasing Odds of Live Birth After IVF/ICSI

By Will Boggs MD

December 10, 2019

NEW YORK (Reuters Health) - Male aging is associated with decreasing odds of live birth in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles for idiopathic infertility, according to a retrospective study.

"Although the worst clinical outcomes are observed when both partners are of advanced reproductive age, there is always a negative effect of male aging even if men partner with young women," Dr. Fabrizzio Horta from Monash University, in Melbourne, Australia, told Reuters Health by email. "We did not predict this. From our animal studies, we were expecting that male age may only become an issue for older females whose eggs have reduced DNA repair capacity."

Male fertility is thought to persist with advancing age, and many men have a second family later in life with a new partner. The effect of paternal age on the outcome of advanced reproductive technologies such as IVF and ICSI remains controversial.

Dr. Horta's team used data from 2,425 fresh cycles of IVF/ICSI to assess the effect of male aging on live birth and other clinical outcomes in 1,506 couples with idiopathic infertility in which male partners had no reported health disorders and were classified as normozoospermic.

In these cases, the indications for standard IVF (41.7%) were previous intrauterine insemination failures and idiopathic infertility, and the indications for ICSI (58.3%) were failure of fertilization with standard IVF and idiopathic infertility.

Of all embryos transferred, 25.1% resulted in a clinical pregnancy and 19.6% resulted in a live birth.

After adjustment for other factors, each year of increase in male age was associated with a 4.1% decrease in the odds of life birth, and each year of increase in female age was associated with a 9.6% decline in the odds of life birth - both statistically significant findings.

There were no significant interactions between male age and female age, the researchers report in Human Reproduction.

As for secondary outcomes, each year of increased age was associated with a 3% drop in the odds of clinical pregnancy for male age and an 8% drop in the odds of clinical pregnancy for female age, as well as a 4.5% increase in odds of miscarriage for male age and an 11.1% increase in odds of miscarriage for female age.

The negative impact of increasing male age on IVF/ICSI outcomes was evident within each category of female age, but the magnitude of this impact on clinical outcomes (except miscarriage) also increased with increasing male age.

In contrast, male age did not show a significant effect on fertilization rates or embryo utilization rates, whereas increasing female age was associated with decreasing fertilization and utilization rates.

"We know that the aging process affects the quality of both male and female gametes even if they look normal, and these outcomes of our study are a clear demonstration of this concept," Dr. Horta said. "Thus, we should aim to develop new strategies that allow us to ensure we are using gametes of the best quality either through improved healthy lifestyles of our patients or by developing new technologies and treatments."

"Even though we know that the aging process is linked to poorer gamete quality, we should foster further investigation and education to help explain the reasons for this," he said. "Finally, the current trend of becoming a parent later in life may have unknown implications that could affect future generations, therefore, establishing aging research in assisted reproductive technologies is now of increasing importance."

SOURCE: Human Reproduction, online November 26, 2019.