Non-obstructive azoospermia is defined in the literature as the absence of sperm in the ejaculate due to a failure in spermatogenesis, representing the most severe form of male infertility. Its etiology is either due to intrinsic testicular damage or inadequate gonadotropin production.
Non-obstructive azoospermia – what it is and why it occurs
Azoospermia is a complete absence of sperm in the ejaculate. A distinction must be made if this absence occurs as a result of an obstruction (obstructive azoospermia) or as a result of abnormal sperm production (non-obstructive azoospermia). Statistically, up to 2% of men in the world do not have a measurable amount of sperm in semen, with azoospermia accounting for up to 10% of cases of male infertility. The problem occurs either from birth or later in life.
Multiple causes for non-obstructive azoospermia are known, including:
– Genetic abnormalities – this category includes Y chromosome microdeletions and karyotype abnormalities (the most common is Klinefelter syndrome and it occurs when a man has an extra X chromosome); up to 10% of patients with non-obstructive azoospermia will have detectable genetic abnormalities leading to reduced sperm production
– Hormonal imbalances – in the situation where there is a deficiency or absence of pituitary hormones, sperm production cannot occur. Men who take or have taken steroids may have hormonal imbalances involved in sperm production.
– Radiation and toxic substances – exposure to chemicals such as heavy metals, chemotherapy and radiation therapy can affect sperm production; for this reason it is recommended to preserve the sperm before starting chemotherapy or radiotherapy.
– Medications – exposure to certain drugs can negatively affect sperm production; an example is testosterone-containing supplements, which can disrupt the normal functioning of the male reproductive system.
– Various medical conditions – certain types of pituitary tumors, testicular cancer, undescended testicles (cryptorchidism) and various immunological causes (post-pubertal orchitis) can affect sperm production
– Varicocele – varicocele is represented by swollen veins in the scrotum, which have a negative impact on sperm production
Diagnosis and treatment for non-obstructive azoospermia
First of all, it is important to have a correct diagnosis of azoospermia, which starts with two semen samples, collected at different times because there are variations in composition that occur naturally; it is important that the sample is brought to the laboratory in a maximum of one hour and that the container is kept at body temperature. Before sampling, it is recommended to avoid ejaculation 2-5 days before so that the body can produce as many sperm as possible. If no sperm are detected in the basic analysis, the sample is inserted in a centrifuge and reanalyzed, with the possibility of finding hidden sperm (cryptozoospermia).
A variant of treatment for men who experience non-obstructive azoospermia is hormone therapy that helps relieve hormonal deficiencies; this may include follicle-stimulating hormone (FSH), human chorionic gonadotropin (HCG), clomiphene, anastrozole or letrozole.
Men who have an abnormal testosterone and estradiol ratio may receive aromatase inhibitors, which improve sperm concentration and motility. Avoiding toxic substances and adjusting the medication by the doctor (when the situation requires it) can also contribute to an increased number of sperm.
Regarding varicocelectomy (varicocele surgery), which involves binding the affected veins and redirecting blood flow to healthy veins, it is useful, but is recommended in severe cases. Up to 40% of men notice that sperm return to sperm after this operation.
Non-obstructive azoospermia and fertility
In the past, fertility doctors believed that the men who had problems producing sperm could only have children with donated sperm or by adoption. However, testicular biopsies of patients with non-obstructive azoospermia often indicate the presence of sperm; although they may have reduced motility, they are used for intracytoplasmic sperm injection (ICSI) during in vitro fertilization (IVF). After several hours of in vitro incubation, the testicular extracted sperm show some motility; the initial absence of motility does not necessarily reflect their viability.
Methods of viable sperm recovery in these patients include fine-needle testicular aspiration (TESA), percutaneous epididymal sperm aspiration (PESA), testicular sperm extraction (TESE), and microsurgical extraction of sperm from the testicle (micro-TES).
Through these interventions, performed under general anesthesia, sperm can be obtained which are later used in assisted reproduction techniques. If there is a genetic cause for non-obstructive azoospermia, genetic testing before the mentioned procedures is indicated. Typical criteria for defective sperm production, including high FSH or reduced testicular volume, do not anticipate the patients who will have viable sperm during the extraction procedure.