In about half of all unintentionally childless couples, the cause of the fertility problem is not caused by the women, but solely or partly by the man. Many different factors can limit male fertility up to and including infertility. However, the exact causes often remain obscure. On the one hand, the process of sperm maturation, the transport of sperm to the egg and the complex fertilization process are still not fully understood. On the other hand, because so many hormonal and enzymatic processes also have to interlock in men that it is often impossible to say exactly where the maturation or fertilization process is disturbed. Therefore, it can happen that even with an inconspicuous spermiogram result, the sperm can only be fertilized with medical assistance.
The most common reason for male fertility disorder is insufficient production of intact and optimally motile sperm. The cause of the disorder may be a previous or current undescended testicle (e.g. inguinal or sliding testicle). In this case, the testicles are not completely or impermanently located in the scrotum, as is required for undisturbed sperm production. Even an unrepaired testicular defect in childhood permanently damages the testicles because they are too warm and possibly also have a poorer blood supply. As a result, not enough sperm are produced. Direct damage to the testicular tissue, such as previous or current infections of the testicles or epididymis, can also permanently impair sperm production. Testicular injuries, such as those caused by sports, or testicular torsion must be medically clarified and treated. Last but not least, thickened veins in the scrotum (varicoceles) are suspected of interfering with sperm production.
Testicular tumors, although rare in the overall population, are nevertheless among the most common male cancers in the age group between 20 and 40 years. Among men with an established fertility disorder, testicular tumors are also significantly more common. Therefore, the disorder is also considered a risk factor for testicular tumor disease. Smoking has a proven detrimental effect on male fertility – both on sperm production and fertilization ability. In addition, the chances of successful artificial insemination are reduced in smokers due to increased DNA damage to the sperm.
Sperm transport disorders
In some men, sufficient sperm are produced, but they are unable to mix with the sperm fluid due to a sperm transport disorder. In these cases, there are too few or no intact sperm in the ejaculate. The reason for this may be (partially) blocked or incompletely formed seminal ducts. In many cases, blocked seminal ducts can be opened microsurgically so that conception is possible again by natural means.
If the seminal ducts cannot be made passable, there is the possibility of sperm extraction in order to freeze them and later prepare them for artificial insemination.
Inadequate urinary bladder obstruction
In some men, the muscular closure between the bladder and prostate does not function sufficiently, resulting in so-called retrograde (backward) ejaculation. In this case, the semen is not transported out through the penis during an orgasm, but is released into the bladder and later excreted with the urine.
In immunological sterility, the man’s immune system treats his own sperm cells as foreign bodies. The result is a defensive reaction against his own body cells (autoimmune reaction). In this case, the immune system attacks the sperm cells by forming defensive substances (antibodies) against them in the blood. These antibodies attach themselves to the sperm and can thus impair both their motility and their ability to reach the egg and penetrate its coating.
The significance of environmental influences, such as those caused by pesticides, organochlorine compounds and other chemical substances, heavy metals, radioactive radiation, or heat is unclear. Although the damaging effect on the human body above a certain level is undisputed, it is seldom possible to prove a clear influence on fertility for the individual. In addition, numerous hormonal and genetic disorders can affect male fertility in a variety of ways. In addition, fertility can be hindered by ejaculation disorders and erection problems.
Last but not least, general diseases of the kidneys, heart and liver, metabolic disorders, and alcohol. Further drug and anabolic abuse can interfere with hormonal balance and initiate fertility-damaging processes.
Is treatment possible?
The causes of a fertility disorder are often beyond one’s control at the time of diagnosis.
The problem often goes back to an early developmental disorder (such as undescended testicles) or an (unnoticed) infection of the testicles or seminal ducts in the past. Nevertheless, medicine can often offer help. Basically, it is important to identify possible causes for fertility disorders and treat them if possible. If fertility cannot be improved or the causes of the fertility disorder are not treatable, it is possible to facilitate the path of egg and sperm cells to each other. This is done with the help of artificial insemination techniques (ART). While they do not eliminate the cause of a fertility disorder, they help to circumvent the effects of a disorder on the sperm’s ability to fertilize.
ART procedures include intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI). Which procedure is suitable depends on the findings of both the man and the woman. This decision approaches the couple as a whole.