Impact of Advanced Paternal Age on Male Fertility

When it comes to fertility and aging, the focus is often on a woman’s ‘biological clock’. However, it’s crucial to understand that men also have a biological clock, and advanced paternal age (APA) can significantly impact male fertility and reproductive outcomes. This blog post aims to shed light on the effects of APA on male fertility, the potential risks associated with it, and the importance of counseling couples about these issues.

Understanding Advanced Paternal Age (APA)

There is no universally accepted definition of APA. However, most professional societies, including the American Society for Reproductive Medicine, define APA as age 40 years and above. This age threshold is significant because it’s around this time that potential impairments in reproductive outcomes can start to occur due to various factors.

APA can negatively affect male fertility in several ways. One of the most significant impacts is the age-related decrease in testosterone levels. This hormonal change can lead to decreases in libido, sexual function, and sexual frequency, thereby reducing opportunities for conception. 

Moreover, lifestyle factors accrued over a lifetime, such as obesity, smoking, and marijuana use, may also contribute to fertility issues in older males.

Effects on Sperm Quality

APA can also negatively affect sperm quality. Studies have shown a decline in semen volume, total sperm count, and motility in older males. There is also a decrease in the percentage of morphologically normal sperm and an increase in DNA fragmentation rates. These changes can potentially impair the ability of the sperm to fertilize an egg and result in a healthy pregnancy.

Lower Success Rates with IVF

APA may also negatively impact the outcomes of assisted reproductive technologies (ART), such as in-vitro fertilization (IVF). Some studies have linked APA to increased rates of miscarriage and lower success rates with ART.

Increased Risk of Genetic Disorders

Advanced paternal age can also increase the risk of certain genetic disorders in offspring. For instance, point mutations in the FGR2 gene can result in increased risk for Apert, Crouzon, and Pfeiffer syndromes.

Approximately 97% to 99% of achondroplasia, a form of short-limbed dwarfism, occurs from a de novo mutation in the FGFR3 gene, mostly from the paternal allele. Mutations in the RET gene can cause multiple endocrine neoplasia, types 2A and 2B.

Furthermore, offspring of females born to older males have an increased risk of X-linked disorders such as hemophilia A and B, Duchenne muscular dystrophy, Hunter syndrome, and Lesch-Nyhan disease.

Increase Risk of Childhood Diseases

There is also a possible association between APA and an increased risk of childhood cancers like leukemia, non-Hodgkin’s lymphoma, pediatric central nervous system tumors, and breast cancer. Further, APA may be a risk factor for certain congenital birth defects, such as cleft lip, diaphragmatic hernia, and heart defects.  Finally, while not conclusive, the literature most strongly supports a link between APA and autism spectrum disorder.

APA and Pregnancy Complications

Female partners of males aged 45 years and above are more likely to develop hypertensive disorders of pregnancy, placental abruption, intrauterine fetal demise, and preterm delivery.

Conclusion: The Importance of Counseling on APA

Given the potential risks associated with APA, it’s crucial that couples are counseled on these effects. This includes altered sperm parameters and reproductive hormones, and increased risk of adverse outcomes such as congenital birth defects, neurocognitive disorders, and pregnancy loss. 

Understanding the impact of APA on male fertility is an essential part of family planning and can help couples make informed decisions about their reproductive health. For more information on this topic, please follow the link in our bio.