Causes of Male Infertility

By Dr Agilan Arjunan, Fertility Specialist, KL Fertility Centre (Malaysia)



‘Male infertility is on the rise’, that’s a fact that many men realise now. However, the bigger question is WHY ?

Are we (the males) doing something wrong or are we not doing something right that is giving rise to male infertility in recent years.

Let us look at what can lead to male infertility . Generally, the causes of male infertility can be broadly divided into :

a) Sperm production problems

b) Sperm transport blockage problems

c) Sexual problems

d) Hormonal and sperm antibody problem (rare)

Worldwide statistics and from my own experience managing male infertility, the majority of men have either sperm production or blockage of sperm transport pathway or a combination of both.

Sperm Production Problems

Just about 10-15 years ago, we don’t hear so much about male infertility.However, the incidence of male factor infertility has risen from about 10-15% to about 40-50% .

Problem with sperm production can either be inherited (genetically-mediated) or non-inherited .

Most common non-inherited causes are lifestyle related. Lifestyle related causes can be modified to improve outcome. Top of the list are smoking , alcohol abuse, obesity and stress.

Cigarette smoke contains numerous chemicals that are harmful for sperm . The chemicals reaches the sperm production ‘factory’ (testicles) via blood stream and affects the balance of certain proteins that are required for optimal sperm production and integrity. This process damages the sperm DNA via oxidative stress by radical oxygens. Radical oxygens can damage any normal cells in our body including sperm cells. Smoking not only makes sperm cells more susceptible to radical oxygens, but smoking itself increases the amount of radical oxygen in the body. Thus, a smoker may have a normal sperm count but the quality of his sperm is very much reduced.

Alcohol abuse also reduces sperm production by lowering the level of the male hormone called testosterone. Testosterone is needed for optimal sperm production. It also can lead to erectile dysfunction. Many health organisations recommend men to avoid habitual drinking or binge drinking. The research  could not conclusively identify the amount of alcohol that affects sperm quality but as little as 5 units of alcohol per week has been shown to have negative effects on sperm.

Besides alcohol, testosterone replacement or abuse can reduce or completely stop sperm production. Testosterone that are consumed (external source to the body) can halt the natural production of hormones that are essential for sperm production. The reversal back to normality sometimes can take years.

Obesity is a well known risk factor for heart disease. Obesity affects sperm production by lowering testosterone. This can happen because fat cells can turn testosterone into female hormone called oestrogen. High levels of oestrogen can reduce sperm production. The other possible reason is the insulating fat increases scrotal temperature thus reducing the optimal environment for sperm production. Obesity also can cause erectile dysfunction.

Stress has long been shown to affect our health. Stress also affects a man’s fertility health. Men with high level of stress has lower sperm quality. The mechanics how stress affects sperm quality is not fully understood but it be related to release of steroids called glucocorticoids which lowers the testosterone level. It is also proposed that stress damages sperm by oxidative-stress.

Sexually Transmitted Infection (STI) can also reduce sperm production by directly damaging the actual site of sperm production in the testicles called seminiferous tubules. Any man suspected to have STI should seek appropriate consultation and treatment to avoid long term fertility health issues.

Varicocele (dilated vein around the testicles) has long been proposed to reduce sperm production. However, only a moderate to large varicocele may impair sperm production. Mild varicocele do not lessen sperm production. Large varicocele increase temperature of the scrotum and testicles.

Failure of the testicles to descend into scrotum during childhood can lead to permanent damage of sperm production. This condition is known as cryptorchidism. Testicles which failed to descend are in a more ‘hotter’ environment compared to its natural position in the scrotum . If treated surgically in early childhood, long term sequelae can be avoided.

Other less common causes are trauma or injury to the genitals , medical treatment such as chemotherapy or radiation and sometime the cause is unknown .

Inherited production problems are rare. Conditions such as Klinefelter’s Syndrome, Y-Chromosome micro-deletion and Down’s Syndrome can lead to either low sperm production or no sperm production (azoospermia).

Sperm Transport Blockage

In this condition, the sperms that are produced are unable to be ejaculated. It is very important to distinguish between semen and sperm. Semen is the combination of fluids from prostate and seminal vesicle. The ejaculate is a combination of semen and sperm.  So, a man could still ejaculate semen without any sperm (azoospermia).

Most common cause of a blocked sperm transport pathway is infections , especially sexually transmitted infection (STI). The inflammatory process damages the structure of sperm transport pathway within and outside of the testicle. However, most of the infections are asymptomatic and difficult to diagnose.

Prostate-related problem such as infection (Prostatitis) or prostate surgery can lead to blockage of sperm pathway. Other pelvic surgery such as for inguinal hernia can, in some cases,contribute to this problem.

In rare cases, vas deference (the tube that transport sperm from testicles into penis) is absence in a condition called Cystic fibrosis. Fortunately, it is more prevalent in the Western countries.

Sexual Problems

In this situation, the problem lies with a proper deposition of sperm in the vagina. Failure of ejaculation , erectile dysfunction and retrograde ejaculation are some common examples.

Sexual problems can be due to an underlying medical condition such as an uncontrolled Diabetes Mellitus or due to trauma to spinal cord. Pelvic or prostate surgery complicated by nerve damage can also lead to erectile dysfunction.

Hormonal and Sperm Antibody

Diseases of pituitary ( a hormone producing gland in the brain) , congenital lack of hormones (FSH & LH) and Kallmann Syndrome can reduce the hormones needed for sperm production . FSH (Follicle Stimulating Hormone) and LH (Luteinising Hormone) are produced in the pituitary and they drive sperm and testosterone production in the testicle.

Vasectomy ( male sterilisation) , injury or infection in the epididymis can lead to sperm antibody production. This sperm antibodies wrongly identify the sperms as a foreign body and destroy the sperm.

Well this is a summary of causes related to male factor infertility. As you can see, majority are lifestyle related. Thus, male partners should come forward for a test and perhaps help can be offered early in their journey towards parenthood.










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