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In recent years, it has been recognized that male age plays an important role in infertility and fertility outcomes. In the past, much attention has been focused on fertility and a woman's age, but research now shows that the father's age can also influence fertility and pregnancy outcomes. The different aspects of male infertility include:
Changes in sexual function: Research consistently shows that aging in men is associated with changes in sexual function that can impact fertility. The decline in sexual function, including erectile dysfunction (ED), increases with age. Between the ages of 40 and 70, the likelihood of severe ED triples and the likelihood of moderate ED doubles.
Spermatogenesis and Age: Spermatogenesis, the process of sperm production, is extensively regulated by hormonal factors. However, as we age, hormonal changes can negatively impact this process. The number of Sertoli cells, which are vital to the process of spermatogenesis, decreases with age, resulting in reduced sperm production. This deterioration in sperm quality can make pregnancy more difficult.
Changes in semen parameters: Age also influences semen quality. Age-related changes can lead to decreased sperm concentration (oligospermia), decreased sperm motility (asthenozoospermia), and abnormal sperm morphology (teratozoospermia). These changes in seminal fluid parameters pose challenges for natural pregnancy. However, reduced testosterone levels can affect fertility through sexual dysfunction (low libido, erectile dysfunction and difficulty ejaculating). Serum testosterone levels are about half to two-thirds lower in men over 70 years of age than in men in their 20s.
DNA fragmentation: Aging is associated with increased oxidative stress, which can lead to DNA damage in sperm. Studies have shown that the rate of DNA fragmentation in sperm increases with age. This affects the genetic integrity of the sperm and can affect the development of the embryo and the outcome of the pregnancy.
Changes in testicular volume: Testicular volume gradually decreases with age, especially from around age 60. This decline is associated with increased gonadotropin levels and decreased bioavailable testosterone, which can further impact fertility.
Diseases and environmental factors: As men age, their risk of developing diseases and being exposed to environmental toxins increases. Medical conditions that require medication, such as antihypertensive and antiandrogenic medications, can negatively impact sperm quality and fertility. For men struggling with infertility, proper screening for these factors is important.
Hormonal Changes: Testosterone levels decline with age, a phenomenon called andropause. This reduction can lead to sexual dysfunctions such as reduced libido, erectile dysfunction and ejaculation problems. Although spermatogenesis continues into old age, hormonal changes can affect fertility.
Miscarriage: The older age of the father is associated with an increased risk of spontaneous abortion in the first trimester of pregnancy. The risk of spontaneous miscarriage increases significantly when the father is 35 years old or older, regardless of the mother's age. If the father was 35 years or older, the risk of spontaneous abortion between 6 and 20 weeks of pregnancy was 1.27. This increased risk was also observed when only couples whose mothers were younger than 30 were examined.
Assisted Reproductive Technology: Father's age can affect the success of assisted reproductive technology (ART). As men age, a decline in fertility and clinical laboratory performance indicators is observed, affecting outcomes such as blastocyst formation and embryo quality.
