Causes of male infertility

Among the causes for sterility and infertility in couples, the ones of strictly male origin represent 20%. All factors that can affect the male fertility are referred to in medical terms as Male Factor.

The main causes that can affect the Male Factor are the following:

-Alterations in the Seminogram results.

-Anatomical alterations of the male genital tract.

-Genetic alterations.

-Systemic diseases.

-Habits and environmental factors.

Alterations in the seminogram results.

Seminograms are diagnostic tests allowing us to assess the quality of semen. Results of a normal seminomgram are known as Normozoospermia.

Its main parameters are:

• Concentration: Calculation of the millions of sperm per millilitre of ejaculated semen. A concentration equal to or greater than 20 million sperm per millilitre in a total volume ejaculated between 2.5 and 6 millilitres is considered normal. Alterations in this parameter are called:
  • Oligozoospermia: When in the total ejaculated there are less than 40 million spermatozoa. When there are less than 1 million sperm per millilitre, it can be classified as mild, moderate or severe.
  • Cryptozoospermia: When the ejaculated semen contains less than 100,000 sperm per millilittre.
  • Azoospermia: It is the total absence of sperm in the semen and affects approximately 2% of males.
  • Motility: It assesses the amount of sperm with fast and rectilinear displacement. When at least 50% of the sperm present this type of movement, the semen is considered to be within normal values. The alteration in this parameter is called Astenozoospermia and is the most frequent sperm anomaly; it means the decrease of the normal mobility of the sperm.
  • Vitality: Assesses the percentage of live sperm in the ejaculate. A percentage equal to or greater than 75% is considered normal. The alteration in this parameter is called Necrospermia and means that all sperm from the ejaculate are dead.
  • Morphology: It measures the percentage of spermatozoa with a normal shape. Values equal to or greater than 30% are considered normal. The alteration in this parameter is called Teratozoospermia which means that there is a high percentage of spermatozoa with abnormal shapes. Along with these main parameters, a seminogram also assesses others such as colour, liquefaction, viscosity, pH or agglutination. These will allow the specialist to guide the diagnosis regarding semen quality.

Anatomical alterations.

In the study of the male factor, it’s important for the specialist to explore the genital tract. Alterations in the urethra, the prostate, the ejaculatory ducts or in the testicles can directly affect the quality of the semen and therefore have an effect on infertility in men.

Among the most frequent anatomical alterations are cryptorchidism and varicocele.

• Cryptorchidism is the lack of descent of one or both testicles into the scrotal sac during the embryonic period. Since one of the main functions of testicles is the formation of sperm. For this, they must be at a temperature lower than the body, in the scrotal sac, the lack of descent causes irreversible damage to the testicle that prevents the sperm formation unless it is surgically corrected in the first months of life.
• Varicocele is the anomalous dilation of the veins of the testicle, which is commonly known as “varicose veins” and which is diagnosed in 40% of males with fertility problems. It can be associated with testicular pain but in many cases it is totally asymptomatic. The presence of varicocele is associated with an increase in “Fragmentation of sperm DNA”, which is why surgical treatment is usually recommended in cases where the degree of fragmentation is high.

DNA is the genetic material carried by sperm. Once it has been compacted, it will form the chromosomes of future individuals. If this material suffers injuries, breaks to a greater or lesser degree in the form of fragments, it compromises the union with the genetic material of the ovule and therefore fertilization.

There are several methods to quantify in a sperm sample the degree of sperm fragmentation, considering that the normal percentage of fragmentation should not exceed 20%.

It is worth mentioning that recently published studies have shown that the continued intake of antioxidants in humans can greatly reduce the degree of fragmentation in many cases.

See our next blog post – “Causes of male infertility (II)” – explaining other affecting causes such as systemic diseases and environmental habits and factors.

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