What are the reasons for infertility in men?
Infertility has been defined as the inability to conceive after 1 year of unprotected sexual intercourse. This condition affects many couples and scientific studies quote a range of 10 to 15%. Out of these, 40% cases are due to male factors, 40% due to female factors and 20% are due to combined factors. A systematic evaluation is required to pinpoint the reasons leading to infertility and provide treatment, with the goal of achieving pregnancy and childbirth.
Reasons for infertility in men
The causes underlying male infertility are numerous. They can be grouped into hormonal, testes related and genital tract related.
Gonadotropin deficiency: This is a genetic disorder called as ‘Kallmann syndrome’ in which there is deficiency in the production of Gonadotropin releasing hormone by the hypothalamus area in brain.
The clinical features include absence of sense of smell, asymmetrical face, color blindness, anomalies of kidneys, micro-penis and absence of testes in the scrotum. There is a delay in the onset of puberty in these patients. The hormonal assessment also shows low levels of testosterone, Leuteinizing hormone (LH) and Follicle stimulating hormone (FSH). The testes in these patients are small due to atrophy with failure of development of germ cells. The fertility can be achieved in these patients with FSH and LH therapy.
Pituitary gland disease: Pituitary gland is a part of brain producing FSH and LH which act on the testes and are responsible for normal male fertility. Damage to the pituitary gland may result due to tumors, death of part of the gland or infarction in sickle cell anemia, surgery, radiation or granulomatous diseases. Pituitary tumors producing excessive amounts of a hormone called prolactin. Elevated prolactin usually results in decreased FSH, LH, and testosterone levels and causes infertility. Associated symptoms include loss of libido, impotence and gynecomastia.
The conditions involving the testes resulting in male infertility include:
- Chromosomal disorders: Klinefelter syndrome is the most common genetic reason for azoospermia or complete absence of sperm cells in the semen.
- Myotonic dystrophy: In these patients the sperm producing seminiferous tubules in the testes are damaged, hence there is infertility.
- Vanishing testis syndrome: Bilateral absence of testes results in infertility. The testes are damaged and lost due to torsion, vascular injury or infection during the fetal growth.
- Sertoli-cell-only syndrome: The germinal epithelium which is responsible for the production of germ cells is absent in the testes.
- Toxins inuced damage of testes: Radiation damages rapidly dividing cells in testes. Drugs like Ketoconazole, spironolactone, alcohol inhibit testosterone synthesis. Recreational drugs like marijuana, heroin and methadone are associated with lower testosterone levels. Cancer chemotherapy destroys rapidly dividing cells including the germ cells.
- Generalized disease: Renal failure, liver failure.
- Testis injury: Orchitis (testicular inflammation), torsion (twisting of spermatic cord), trauma. If the testicular torsion is diagnosed and corrected surgically within 6 hours of occurrence, the testis can usually be saved.
- Cryptorchidism: Congenital absence of testes in scrotum
- Varicocele: Presence of dilated and tortuous veins in the scrotum
Genital tract related causes of infertility
The genital or the reproductive tract includes the epididymis, vas deferens, seminal vesicles and associated ejaculatory apparatus. The important causes which affect the genital tract leading to infertility include reproductive tract obstruction, disorders of sperm movement or function. Any obstruction in the reproductive tract prevents the passage of sperms to come out. The blockage can be by birth, like absence of vas deferens, epididymal obstruction or ejaculatory duct obstruction. The acquired causes include vasectomy, groin surgery and local infection. Nerve injury may also result in blockage due to lack of function. Disorders of sperm function or motility are seen in conditions like immotile cilia syndromes, sperm maturation defects and immunologic damage to sperm cells.
Male infertility is a sensitive issue as it also involves the male ego. It should be handled carefully by convincing both partners to undergo simultaneous assessment. A systematic and stepwise approach usually results in fruitful outcome.