Male Factor Infertility
Male factor is responsible for a couple's infertility in 50-60% of cases, and in more than half of these cases, the male has the only infertility problem. There are several potential causes of male factor infertility:Hormonal
Hormonal causes can be due to problems at the hypothalamic-pituitary level or at the testicular level. Normally, the hypothalamus regulates pituitary production of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). FSH and LH drive the testis to produce sperm and testosterone. Deficiency of FSH or LH can lead to a diminished drive of testicular production of sperm and testosterone, just as lack of gas will prevent a car from being able to run. Today, the most common reason for a man to have FSH and LH production shut off is from his use of anabolic steroids such as testosterone and hcg (human chorionic gonadotropin). These may provide negative feedback on the pituitary, thereby shutting down FSH and LH production. One can also see elevated testosterone turning off testicular sperm production with congenital adrenal hyperplasia and adrenal tumors.
Pituitary tumors, infarction, surgery, radiation and infiltrative processes can also diminish FSH and LH production. In the presence of low FSH and LH it may be useful to check for elevated prolactin levels to rule out a pituitary prolactinoma and obtain an MRI to check for other tumors or pituitary pathology.
Isolated deficiency of LH and FSH can occur (Kallmann's syndrome) and lead to diminished testis (hypogonadism). This occurs in 1 in 10,000 men. Less common defects are seen in hypothalamic stimulation of the pituitary and are usually associated with other congenital findings.
Abnormal thyroid and glucocorticoid (prednisone) excess can result in decreased spermatogenesis through effects on the hypothalamus and LH production or conversion of androgens (male hormone) to estrogens.Testicular
Testicular causes of infertility include the presence of tumor, chromosomal abnormalities, congenital absence of germ cells, drugs and radiation that are toxic to the testes, undescended testes and varicocoele.
Ten per cent of males with a sperm count fewer than 10 million and 20% of men with azoospermia (no measurable level of sperm in the semen) have a chromosomal abnormality. Kleinfelter's syndrome is a genetic disorder due to the presence of an extra x chromosome in the male. This occurs in 1 out of 500 males and is often seen in the mosaic form where some cells are 46 xy and some are 47 xxy. The testes tend to be small and these men have delayed sexual maturation, azoospermia and gynecomastia (enlarged male breasts). There has been some success with ICSI of biopsied immature sperm cells.
Sertoli-cell only syndrome or germinal cell aphasia may have several causes including congenital absence of the germ cells, genetic defects or androgen resistance. Testicular biopsy shows complete absence of germinal elements. Men are azoospermic yet virilize normally. Testes may have normal consistency but be slightly smaller in size. Testosterone and LH levels are normal but FSH is usually elevated. Men with testicular failure secondary to mumps, cryptorchidism or radiation/chemotherapy damage have smaller testes with a non-uniform histologic pattern. The testes may have severe sclerosis and hyalinization. There is no treatment for this form of azoospermia.
Gonadotoxic drugs like chemotherapy or radiation can affect the germinal epithelium because it is a rapidly dividing tissue and is susceptible to the interference imposed by these toxins on cell division. At radiation exposure below 600 rads, germ cell damage is reversible. Recovered spermatogenesis may take up to 2-3 years even when exposed to low doses of radiation. Elevated FSH levels reflect the impaired spermatogenesis and return to normal once the testes recover.
Orchitis occurs in 15-25% of males who contract mumps, which is unilateral in 90% of cases. Testicular atrophy may take years to develop. At least two thirds of men with bilateral orchitis remain infertile for life.
Trauma either through accident or torsion of a testis is a relatively common cause of subsequent atrophy with potential diminished fertility.
Medical conditions such as renal failure, cirrhosis of the liver and sickle cell disease can all lead to low testosterone levels and decreased spermatogenesis.
Cryptorchidism occurs in 1 in 12 males. The undescended testis becomes abnormal after age 2. Even when unilateral, cryptorchid patients have reduced fertility potential.
The varicocoele is the most common finding in infertile men. It is the result of backflow of blood due to incompetent valves in the spermatic veins. 90% occur on the left and is found in 20% of males, 40% of the infertile population. 50% of men with varicocoeles are fertile. It is thought that a varicocoele can cause infertility by elevating the temperature of the testis. Varicocoelectomies however are not universally helpful and remain somewhat controversial for many cases of infertility.
Other causes of azoospermia include congenital absence of the vas deferens or obstruction secondary to infection or surgery. These cases may be amenable to surgical reconstruction and/or ICSI with epididymal aspiration or testicular biopsy to obtain sperm. These are the most successful cases of ICSI associated with azoospermia.Sperm Antibodies
Sperm antibodies may be a relative cause of infertility in about 3-7% of cases. Treatment has been successful with intrauterine insemination and with ICSI.Infection
Infections can affect sperm motility secondary to e coli, Chlamydia, mycoplasma, ureaplasma and trichomonas. Culture and treatment for asymptomatic infertile males remains controversial.Sexual Dysfunction
Sexual dysfunction is a presenting cause of male infertility in about 20% of cases. Decreased sexual drive, erectile dysfunction, premature ejaculation and failure of intromission are all potentially correctable causes of infertility.Idiopathic Infertility
Unfortunately, at least 25-40% of infertile men have idiopathic infertility for which no cause may be identified.