There are certain diseases that can have a decrease in the number of sperm as a symptom; for this reason, in many occasions oligospermia appears together with other affections.
The presence of varicocele can significantly reduce the sperm quantity within the testicles. Spermatogenesis is the process through which sperm are formed: a meiosis happens and, from a diploid cell that contains all genetic information, we pass to a haploid cell with half of the genetic content. For this division to take place, the presence of the enzyme DNA polymerase (which is thermally sensitive) is necessary. During the obstruction in the sperm tube (varicocele), this enzyme’s effectiveness decreases, and less sperm are synthesized.
It is a buildup of fluids around the testicle that usually appears in men older than 40. In some patients, sperm parameters are altered. With the volume increased of the testicular zone, due to a retention of the serous fluid, the vas deferens in charge of the transportation of sperm can be partially obstructed, reducing the number of sperm in the ejaculate and causing oligospermia – although this relation is made in 10% of the occasions.
Men with a poor seminal quality can possibly have an affected seminal parameter, as well as more than a seminal factor can be altered. For example, it is frequent that men with oligospermia have also an important amount of sperm with an altered morphology: this relation is known as teratospermia. Sperm’s abnormalities complicate the fertilization in a normal way, and are also connected to a bad outcome of embryo’s development.
Asthenozoospermia is another sperm alteration, characterized by a poor quality of the sperm movement. Sperm must be able to move fast: once ejaculated, they must pass through the female tract, until they reach the egg within a fallopian tube. In some men, oligospermia exists with asthenozoospermia, reducing their reproductive potential, in comparison with men with normospermia (those whose seminal values are normal).