“Younger” sperm contributes to higher probability of pregnancy
The biologic age of male sperm can determine the success of pregnancy as well as the time it takes to become pregnant, revealed Dr. J. Richard Pilsner, the Director of Molecular Genetics and Infertility, part of a research team studying male fertility at the Wayne State University School (WSU) of Medicine in the US.
WSU researchers explain that sperm epigenetic aging is the biological, rather than the chronological, aging of sperm which is a better gauge of reproductive success. According to their study of some 380 couples – focusing on the male partners – there was a 17% lower cumulative probability of pregnancy after 12 months for couples with male partners in older compared to younger sperm epigenetic aging categories.
The study also found higher epigenetic aging of sperm in men who smoked.
The results indicate that a higher sperm epigenetic age is associated with a longer time to become pregnant in couples not assisted by fertility treatment, and among couples that achieved pregnancy, with shorter gestation.
Semen quality, while used to assess male infertility for decades, are poor predictors of reproductive outcomes. It is therefore important to understand sperm epigenetic aging and pregnancy probability and its slowing or reversal through lifestyle choices and/or pharmacological interventions through further, more diverse investigation.
In addition, because older fathers have an increased risk of children with adverse neurological outcomes, it is important to understand the potential relation of sperm epigenetic aging on children’s health and development, said Dr. Pilsner.
“While chronological age of both partners remains a significant predictor of reproductive success, our clocks likely recapitulate both external and internal factors that drive the biological aging of sperm,” explained Dr. Pilsner. “Such a summary measure of sperm biological age is of clinical importance, as it allows couples in the general population to realise their probability of achieving pregnancy during natural intercourse, thereby informing and expediting potential infertility treatment decisions; the ability to capture the biological age of sperm may [also] provide a novel platform to better assess the male contribution to reproductive success, especially among infertile couples.”
