Although significant focus has been placed on female reproductive aging, there is also an age-related decline in sperm function and male fertility.
There is a decline in testicular function, which includes declining testosterone levels each year.
Sperm parameters including semen volume, motility, and morphology decrease with age, although a decline in sperm concentration has not been shown.
Most studies suggest that male age does not affect IVF/ intracytoplasmic sperm injection pregnancy rates despite lower motility and fertilization rates.
There was also no difference seen in egg donation cycles.
In couples undergoing ART treatment, it appears that the effect of paternal age > 40 years of age has
- Little effect on cleavage-stage embryos.
- Significant decreased rates of blastocyst formation
- Decrease in the number of cryopreservable embryos.
- Associated with increased risk of spontaneous miscarriage
- In combination with a maternal effect, paternal effect may increase the risk of Down syndrome.
- Associated with autosomal dominant disorderssuch as Alport syndrome, achondroplasia, and neurofibromatosis.
- Increased association with Autism spectrum disordersand schizophrenia
Men > age 40 and their partners should be counselled about these potential risks when they are seeking pregnancy, although the risks remain small.