Controversy exists as to whether embryonic development is influenced by the age of the male partner. Since older men tend to reproduce with older women, it is difficult to eliminate from population studies the influence that the aging woman has on reproductive potential. Although studies have demonstrated that aging increases aneuploidy as a result of meiotic abnormalities in the woman, the question remains whether a similar dysfunction exist in the man affecting fertilization rates or altering embryo development ultimately leading to a decrease in pregnancy potential.
Using the Oocyte Donor IVF Model to study the effect of a Male’s age on Reproduction.
Although a substantial body of evidence supports the conclusion that maternal age adversely impacts fertility, the effect of the aging male gamete on fertility has been studied less conclusively. Oocyte donation IVF cycles represent an important way to evaluate the male contribution to reproductive outcomes. Since in oocyte donation all oocytes are obtained from a young homogeneous population of oocyte donors with good eggs and great reproductive potential, oocyte donation represents an optimal model to study the influence of male aging on reproductive potential.
In 2008, I published an article in the Fertility & Sterility Journal using a donor egg IVF population looking at the effect of male age on human reproduction. At that time, there were very few articles devoted to that topic and most providers had assigned the majority of the reproductive success and failure to the egg (oocyte). The data in our study indicated there was little effect of paternal age on fertilization and early embryo development in patients undergoing IVF. However, paternal age did affect later embryonic development, miscarriage rates, and live birth rates.
Using oocytes donated by women younger than 35 years greatly decreased the bias and effect of the female age on outcome rates. A decreasing trend in implantation rate and live birth rate as well as an increasing trend in miscarriage rate was noted in men older than 55 years.
The purpose of our study was to evaluate men desiring to reproduce in their reproductive years; therefore, the oldest male in our population was 60 years. We noted a significant linear decrease in semen volume and total motility without a significant decrease in concentration, percent motility, or percent morphology. In the past, other studies have documented similar declining semen parameters in older men seeking reproductive help.
In summary, our study was unique in that it in addition to evaluating fertilization rates and outcome rates, we thoroughly evaluated embryo morphology and embryo development. With the exception of semen volume and total number of motile sperm, our data demonstrated that sperm characteristics do not seem to be affected by male age, at least up to age 60 years. Sperm’s ability to penetrate human eggs, the characteristics of the resulting embryos and embryo development do not seem to be altered significantly by aging of sperm. While we did note a trend for lower live birth rates and higher miscarriage rates, the outcome rates during ART are minimally altered in the older male population.