Male fertility disorders

In about half of all couples who are unable to conceive, the cause of the fertility problem lies not with the woman, but solely or partly with the man. Many different factors can impair male fertility, even leading to infertility. However, the exact causes often remain unclear. On the one hand, this is because the process of sperm maturation, the transport of sperm to the egg, and the complex fertilization process have not yet been fully researched in detail. On the other hand, because so many hormonal and enzymatic processes must interact in men that it is often impossible to determine exactly where the maturation or fertilization process is disrupted. Therefore, it can happen that even with a normal semen analysis result, sperm are only capable of fertilization with medical assistance.

Disorders of sperm production

The most common cause of male infertility is insufficient production of intact sperm with optimal motility. This condition may be caused by a past or current undescended testicle (e.g., inguinal or floating testicle). In such cases, the testicles are not fully or consistently located in the scrotum, as is necessary for normal sperm production. Even an untreated undescended testicle in childhood causes permanent damage to the testicles, as they are too warm and may also have poorer blood flow. As a result, insufficient sperm is produced. Direct damage to testicular tissue, such as past or current infections of the testicles or epididymis, can also have a lasting negative impact on sperm production. Testicular injuries, such as those caused by sports, or testicular torsion must be medically evaluated and treated. Last but not least, enlarged veins in the scrotum (varicoceles) are suspected of interfering with sperm production.
Although testicular tumors are rare in the general population, they are nevertheless among the most common cancers in men aged 20 to 40. Testicular tumors also occur significantly more frequently in men with a diagnosed fertility disorder. For this reason, the disorder is also considered a risk factor for testicular cancer. Smoking has a proven detrimental effect on male fertility—affecting both sperm production and sperm fertilization capacity. Furthermore, the chances of success with artificial insemination are reduced in smokers due to increased DNA damage in the sperm.

Disorders of sperm transport

Although some men produce enough sperm, a blockage in the sperm transport system prevents the sperm from mixing with the seminal fluid. In these cases, there are too few or no intact sperm in the ejaculate. This can be caused by (partially) blocked or incompletely formed sperm ducts. In many cases, blocked sperm ducts can be opened using microsurgery, making natural conception possible again.
If the sperm ducts cannot be made passable, it is possible to collect sperm, freeze it, and later prepare it for artificial insemination.

Inadequate bladder closure

In some men, the muscular sphincter between the bladder and the prostate does not function properly, resulting in what is known as retrograde ejaculation. In this condition, during orgasm, semen is not expelled through the penis but is instead released into the bladder and later passed out in the urine.

Antibody production

In cases of immunological sterility, a man’s immune system treats his own sperm as foreign bodies. The result is an immune response against the body’s own cells (autoimmune reaction). In this process, the immune system attacks the sperm by producing antibodies against them in the blood. These antibodies attach themselves to the sperm and can thereby impair both their motility and their ability to reach the egg and penetrate its membrane.

Unclear causes

The role of environmental factors—such as pesticides, organochlorine compounds, and other chemicals; heavy metals; radioactive radiation; or heat—remains unclear. Although their harmful effects on the human body are undisputed above a certain threshold, it is rarely possible to demonstrate a clear impact on an individual’s fertility. In addition, there are a number of hormonal and genetic disorders that can impair male fertility in various ways. Furthermore, fertility can be hindered by ejaculation disorders and erectile dysfunction.
Last but not least, general diseases of the kidneys, heart, and liver, metabolic disorders, and the abuse of alcohol, drugs, and anabolic steroids can disrupt hormonal balance and trigger processes that impair fertility.

Is treatment possible?

By the time a diagnosis is made, it is often no longer possible to influence the causes of infertility.
The problem is often due to an early developmental disorder (such as undescended testicles) or a past (unnoticed) infection of the testicles or sperm ducts. Nevertheless, medical treatment can often help. The basic approach is to identify possible causes of the fertility problem and treat them if possible. If fertility cannot be improved or if the causes of the fertility problem cannot be treated, it is possible to facilitate the path of the egg and sperm toward each other. This is done using assisted reproductive technologies (ART). While these do not eliminate the cause of the fertility problem, they help circumvent the effects of the problem on the sperm’s ability to fertilize.

ART procedures include intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI). The choice of procedure depends on the results of both the man’s and the woman’s evaluations. This decision always involves the couple as a whole.