When discussing fertility, our discussions predominantly centre around the topic of female fertility, encompassing aspects such as egg quantity, age-related changes in egg quality, and the advantages of egg freezing as a means to preserve reproductive options for future parenthood.
However, it is worth acknowledging that an estimated 30% of infertility cases fall under the category of “male-factor infertility,” where concerns related to eggs do not come into play. With this in mind, let us delve into the equally significant dimension of fertility – that of sperm health.
Men produce 200-300 million sperm daily
Men produce 200–300 million spermatozoa daily, equivalent to around 1,500 sperm every second. A healthy individual can release between 80–300 million sperm per ejaculation.
In stark contrast to eggs, which are established in utero and remain constant throughout a person’s life, sperm is a continuous creation. This ongoing process, known as “spermatogenesis,” transpires within the testes and is under the influence of various male hormones, including testosterone. While spermatogenesis spans approximately 2 ½ to 3 months, the constant nature of this process ensures a steady supply of sperm. This means that new sperm cells commence their development and reach maturity on a daily basis.
Spermatogenesis initiates at puberty and continues throughout a man’s lifetime, thus eliminating concerns of “running out” of sperm, a concern akin to the finite supply of eggs. Nonetheless, sperm health can be influenced by age and lifestyle factors, a subject we will explore further.
Sperm’s Primary Composition
Sperm cells, the male gametes responsible for fertilization when they encounter an egg, are haploid, harboring half the usual number of chromosomes (23) compared to a typical cell (46) found in the body. Consequently, when a healthy sperm fertilizes a healthy egg, they unite to create a diploid cell containing 46 chromosomes.
The genetic material resides within the sperm’s head, a minuscule structure measuring about 0.05 millimeters or 0.002 inches, which is approximately 1/30th the size of an egg. Additionally, a sperm comprises mitochondria, which provide the energy necessary for the tail’s movement, essential for the sperm’s impressive swimming ability, propelling it at a rate of about 8 inches per hour, an impressive feat considering its diminutive size.
Key Determinants of Sperm Health
The assessment of sperm health relies on several critical characteristics, including:
1. Concentration: Referring to the number of sperm present per milliliter of semen, a healthy sperm count typically ranges from 15–20 million per milliliter or higher. Oligozoospermia denotes a low sperm concentration, while azoospermia signifies a complete absence of sperm.
2. Motility: This pertains to a sperm cell’s ability to move independently, especially its swimming motion. A given sample should ideally contain 40–50% or more motile sperm. Reduced sperm motility is termed asthenozoospermia.
3. Morphology: Morphology concerns the structure, size, and shape of sperm, crucial for its ability to penetrate an egg during fertilization. Ideally, at least 4% of sperm within a sample should exhibit proper morphology. Teratozoospermia signifies an elevated presence of abnormally shaped sperm within a semen sample.
4. Genetic Health: Similar to eggs, sperm may harbour genetic abnormalities that compromise their capacity to generate a healthy embryo. Unlike eggs, sperm’s genetic health is not solely linked to age but may be influenced by other factors such as infection, elevated body temperature, or lifestyle choices such as smoking or drug use.
These parameters of sperm health, with the exception of genetic health, are typically assessed as part of a comprehensive semen analysis.
The Impact of Lifestyle on Sperm Health
While the ageing process has limited influence on the well-being of eggs nestled within ovaries, sperm are highly susceptible to a range of lifestyle and medical factors due to their perpetual production. Although the list is not exhaustive, we have outlined key factors with substantial evidence below:
Activity Level and Weight: Several studies have demonstrated a positive correlation between regular exercise and enhanced sperm health and count. Additionally, it has been theorized that exercise may elevate testosterone levels, and shedding excess weight can also contribute to improved sperm health. Conversely, obesity has been associated with a lower sperm count, decreased motility, and compromised sperm health.
Smoking: The consensus among medical experts underscores the detrimental impact of tobacco smoking on male fertility. Meta-analyses of data from over 10,000 subjects conclude that smoking is linked to lower sperm count, higher instances of oligozoospermia, and elevated levels of morphological defects.
Alcohol Consumption: Excessive alcohol intake, particularly consumption of five or more drinks per week, has been linked to reduced sperm concentration, total sperm count, and a lower percentage of sperm with normal morphology. Those who consume over 40 drinks per week have experienced a 33% reduction in sperm concentration compared to individuals consuming 1–5 drinks per week.
Substance Use: Anabolic steroids represent one of the top substances that can compromise sperm health, leading to significantly lower levels of motile and morphologically normal sperm. Cocaine use over the long term is associated with lower sperm counts and reduced motility and morphology. On the other hand, research on marijuana presents mixed results.
Exposure to Toxins: Individuals in certain occupations may be at a higher risk of toxin exposure, a factor more than twice as likely to affect those with conditions like oligozoospermia, asthenozoospermia, or teratozoospermia as compared to fertile individuals. Occupations such as agriculture, herbicide handling, plastic production, and military service have been associated with worsened sperm parameters due to exposure to various harmful substances.
Medications and Medical Treatments: Certain medications and medical treatments, particularly cancer therapies like chemotherapy and radiation, can significantly affect sperm health. Chemotherapy, administered systemically, can damage sperm cell production and affect the testicles’ ability to produce testosterone. Radiation therapy can also disrupt or halt sperm production. Moreover, several medications, such as antidepressants, alpha-blockers, ketoconazole, antibiotics, opiates, and antipsychotics, may influence sperm health.
Initiating Positive Changes
The encouraging aspect is that since sperm production is an ongoing process, the detrimental effects of medications and behaviors can often be reversed. Considering the sperm production lifecycle, it takes roughly 2 ½ to 3 months for healthier sperm to become evident in a semen sample following positive lifestyle modifications.
Age and Sperm Health
Although the connection between age and sperm health isn’t as pronounced as with eggs, it is still noteworthy. Couples with older fathers, particularly those over 40, may encounter lower pregnancy rates and higher miscarriage rates. Sperm motility and morphology have been observed to decrease with advancing age, with studies indicating an annual decrease in motility and morphology percentages. Additionally, a child’s risk of birth defects, schizophrenia, and autism rises with the father’s age.
Semen Analysis
A semen analysis offers invaluable insights into sperm health and is a relatively straightforward and non-invasive test. Typically, it involves providing a semen sample obtained through masturbation or with the use of a special condom during intercourse. The sample is then examined under a microscope, enabling healthcare professionals to assess sperm count and concentration and the percentage of motile and morphologically normal sperm. Semen analysis also typically includes an evaluation of semen chemistry and volume.
Semen analysis can be performed at fertility clinics, urologist offices with andrology labs, or at select laboratory companies with a doctor’s requisition. Recently, home-based and mail-in tests have become available for added convenience, although many of these tests solely assess sperm count, which represents only one facet of sperm health.
Additionally, there is a diagnostic tool called the sperm chromatin structure assay (SCSA), which identifies sperm samples with high levels of DNA fragmentation. This test delves into sperm health at a genetic level, offering insights not obtainable through conventional semen analysis.
Sperm Freezing: A Valuable Option
Much like egg freezing, sperm freezing provides a means to preserve sperm quality and health. It is invaluable for individuals embarking on cancer treatments, military deployments, or occupational toxin exposure. It also serves as a valuable resource for couples undergoing fertility treatments. The sperm freezing process is efficient and straightforward, encompassing semen collection, sperm washing, freezing, and long-term storage. Frozen sperm can be preserved indefinitely without a loss in quality, ensuring a reliable source for various fertility procedures, including intrauterine insemination (IUI) and in vitro fertilization (IVF).
Anna Haotanto is the Founder of Zora Health and a passionate advocate for women’s empowerment. Anna’s personal experiences with egg-freezing, PCOS and the challenges of fertility have fueled her mission to provide high-quality information, financing, and support to help women and couples navigate their fertility journeys with confidence. She is also recognised for her achievements in finance, entrepreneurship, and women’s empowerment, and has been featured in various media outlets. You can also follow her on Linkedin or Instagram.
