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  • Writer's pictureMaryam Rahbar

The most common causes of male infertility

Male infertility is on the rise with the complexity and prevalence being underestimated due to lack of access to infertility care. Which is why there is a great need to better understand the causes as well as increase awareness regarding male fertility.

To do this, it is important to understand what factors may cause concern for anyone with sperm with regard to their fertility. There are many factors that can cause or contribute to male infertility. Some of these factors have reversible negative effects which can be treated with either lifestyle changes or medical interventions.

At Jack Fertility, we believe that anyone with sperm should have the opportunity to test their fertility potential to be able to take control and better understand what changes and treatments are needed.

Let us delve a bit further into the causes of infertility.

The causes can be separated into lifestyle choices, medical conditions, and environmental factors some of which are outlined in this post.

It is important to test your fertility potential and if there are any issues to understand what factors could be causing problems. The main medical causes of male infertility include:

  • Infection – leading to inflammation of the epididymis or testicles which may block the passage of sperm. Sexually transmitted infections such as gonorrhea, chlamydia, and HIV can also affect sperm health. With infections, most are treatable with the sperm damage being reversible if detected and treated early. It is, therefore, important to check overall health parameters regularly [1].

  • Varicocele – this is a swelling of the veins which drain the testicles creating abnormal blood flow. There are varicocele treatment options that can result in the regeneration of the sperm parameters. It is also important to note that not all those with varicocele will have fertility issues [2].

  • Ejaculation problems – retrograde ejaculation, premature ejaculation, delayed ejaculation, and anejaculation (inability to ejaculate) can all be causes of male infertility since the sperm will not enter the female’s reproductive system. The volume of semen will be affected if there are any ejaculation problems [3]. Other problems with sexual intercourse such as erectile dysfunction, painful intercourse, and psychological issues related to sex can also be cause for concern when considering male fertility.

  • Anti-sperm antibodies – these are immune system proteins that mistakenly target and attack sperm and negatively affect sperm quality. Antibodies are typically used by the immune system to target foreign invaders but in some cases can target sperm which can be caused by injury/trauma, vasectomies, infections, and obstruction [4].

  • Tumours/cancer – Tumours that affect the release of hormones through the pituitary gland can affect sperm production and will need to be treated. Cancer treatment such as chemotherapy can negatively affect sperm production and fertility. It is routinely recommended to have a semen analysis performed prior to cancer treatment and potentially have sperm samples frozen for future use [5].

  • Undescended testes – if one or both testicles have failed to descend from the abdomen into the scrotum then this can lead to reduced fertility. If surgery is performed at a young age, there will likely be no negative effects on fertility. However, without treatment, the chances of natural conception will be greatly reduced [6].

  • Hormonal imbalances – Hormones such as testosterone are required for sperm production. Problems with any of the hormonal systems (hypothalamus, pituitary gland, adrenal gland and/or thyroids) can influence fertility [7].

  • Tubal defects – any defects in the tubal system (the tubes in the testicles, tubes that drain the testicles, the epididymis, the vas deferens, and the urethra) which carry sperm will block the passage and result in infertility. These blockages may be a result of infection, injury/trauma, or developmental issues such as with cystic fibrosis. Previous surgeries such as vasectomy, scrotal or testicular surgeries, or prostate surgeries may affect sperm and their effects should be investigated if there are issues with conception.

  • Chromosomal defects – Inherited disorders such as Klinefelter’s can lead to male fertility issues through abnormal development of the male reproductive system.

Other than medical conditions and lifestyle choices that could affect sperm, there are also environmental factors that could have negative impacts on sperm quality. It is worth looking a bit more into these factors to understand what to look out for when starting to think about your fertility.

Although certain environmental exposures may be difficult to avoid, it is beneficial to have an idea of their impact on fertility so that you can get tested early on and avoid prolonged exposures.

What are some of these environmental factors that can affect sperm?

  • Industrial chemicals – endocrine-disrupting chemicals such as pesticides, herbicides, and organic solvents can affect sperm parameters after prolonged exposure [8].

  • Heavy metals – Cadmium, aluminum, and lead are metals that are commonly found in an industrial setting and can produce free reactive oxygen species which can affect sperm parameters [9].

  • Overheating the testicles – The testicles are approximately 3°C lower in temperature compared to the normal body temperature which is optimal for the process of sperm production, maturation, and storage. Increased temperature (especially prolonged, for example, due to occupation) reduces sperm concentrations and sperm motility [10]. This is a result of DNA damage and reduced energy production by the sperm.

What can I do if I suspect that my fertility is at risk?

The factors mentioned here may have a negative impact on male fertility. The detrimental impacts can be seen after prolonged periods of time without assessment and possible treatment options.

The first step to better understanding male fertility potential, and whether changes need to be made or more specialist advice should be sought, would be to have a semen analysis which will look at different parameters of the semen and provide an insight into sperm quality, which I explained in depth here.

At Jack Fertility, we provide an easy-to-use at-home semen analysis kit which can be mailed back to us, at your convenience, for lab-grade results that will provide the necessary information for anyone with sperm to learn about their fertility. Having the right information can help in reversing the negative effects of some of these factors either through lifestyle changes or through medical interventions.

Sign up for early access to a Jack kit here.

Maryam Rahbar MSc DPhil (Pending, Oxon) is the Chief Scientific Officer of Jack Fertility



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