New measure of sperm age may be an indicator of pregnancy success

A recent study published by researchers at Wayne State University School of Medicine shows that a new technique for measuring the age of male sperm has the ability to predict the success and time it takes to conceive.

“The epigenetic clock of sperm is associated with pregnancy outcomes in the general population,” Published in the journal Human Reproduction, finding that the epigenetic aging of sperm, the clocks may act as a new biomarker for predicting gestational time for couples. The findings also emphasize the importance of the male partner to reproductive success.

J. Richard Pilsner, Ph.D.,

“Chronological age is an important determinant of reproductive capacity and success among couples trying to conceive, but chronological age does not sum up cumulative genetic and external-environmental factors, and thus serves as a proxy measure for the ‘true’ biological age of cells,” said J. Richard Pilsner, PhD, lead author of the study. Dr. Pilsner is Robert J. Sokol, MD, associate chair of Molecular Obstetrics and Gynecology and Director of Molecular Genetics and Infertility at WSU’s CS Mott Center for Human Growth and Development. “Semen quality results using WHO guidelines for assessing male infertility have been used for decades, but remain a poor predictor of reproductive outcomes. Thus, being able to capture the biological age of sperm may provide a new platform for better assessing male contribution to reproductive success,” Especially among infertile couples.”

Epigenetic aging of sperm is biological aging, not sperm chronology. The study found a 17% lower cumulative probability of conception after 12 months for couples with older male partners compared to the epigenetic aging categories of younger sperm. The study included 379 couples who had stopped using contraception in order to conceive.

The study also found higher epigenetic aging of sperm in men who smoke.

Dr. Pilsner said the findings suggest that higher epigenetic aging of sperm is associated with a longer gestation time in couples not helped by fertility treatment, and among couples who achieved gestation with shorter gestations.

The strong association between the epigenetic aging of sperm and the possibility of pregnancy and its slowing or reversal through lifestyle choices and/or pharmacological interventions requires further investigation. In addition, because older fathers have an increased risk for children with adverse neurological outcomes, it is important to understand the potential relationship of the epigenetic aging of sperm to the health and development of children.

“New measures of male fertility are urgently needed to assess overall reproductive success among couples in the general population,” Dr. Pilsner said. ‚ÄúThese data show that our epigenetic clocks for sperm may satisfy this need as a new biomarker that predicts pregnancy success among couples who do not seek fertility treatment. While the chronological age of both partners remains an important predictor of reproductive success, our clocks likely summarize external factors and intrinsic factors that drive the biological aging of sperm. Such a summary measure of the biological age of sperm is of clinical importance, as it allows couples in the general population to realize the likelihood of achieving pregnancy during normal intercourse, thereby informing and accelerating potential infertility treatment decisions.”

Dr. Pilsner advised that because those studied were largely Caucasian, larger and more diverse cohorts are necessary to confirm the association between the epigenetic aging of sperm and the success of marital pregnancy in other races and races.

The research was funded in part by grants from the National Institute of Environmental Health Sciences and the National Institutes of Health (R01ES028298 and P30 ES020957); and Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD (contracts N01-HD-3-3355, N01-HD-3-3356 and N01-HD-3-3358).