Causes of infertility

Male infertility

Male infertility is defined as the inability of a man to father a child. Although male infertility may be associated with impotence, many infertile men have perfectly normal and happy sexual relationships.

Male infertility can be classified into four main types:

• No sperm (azoospermia) accounts for 3-4% of male infertility.
• Poor sperm quantity (oligospermia) or quality e.g. low motility (asthenozoospermia) or a high percentage of abnormal sperm (teratozoospermia). Antisperm antibodies, etc. This subgroup may account for about 90% of male infertility.
• Sperm dysfunctional, where there is a normal semen analysis but the sperm lack or have a defective fertilizing capacity, resulting in complete failure of fertilization or poor fertilization of the eggs in IVF. This accounts for 3-6% of male infertility.
• Inability to ejaculate into the vagina. This accounts for 4-6% of male infertility.

In the majority of men suffering male infertility, physical and genital examinations reveal no cause of infertility, but in a few cases, it may reveal abnormalities such as poor facial and bodily hair, enlarged breasts, undescended testis, small testes or varicocele.

Incidence

20-30%

Causes

Male infertility due to no sperm in the ejaculate.

Possible causes include either failure of the testicles to make sperm, or the testicles are making sperm but because the vas deference are either blocked or congenitally did not develop, no sperm is seen in the ejaculate. In the majority of men in whom the testicles are not making sperm, there is no apparent reason. However, in a few there is history of trauma to the testicles, severe mumps infection after puberty, or the pituitary gland is not producing enough hormones. Chemotherapy or radiotherapy for cancer might have damaged the testicles.

Semen freezing should be made available to men undergoing medical treatment that is likely to make them infertile as effectiveness of semen freezing is well established.

Genetic defects e.g. chromosomal abnormality such as Klinefelter's syndrome, and Y chromosome deletion (a tiny abnormality in the area of a Y chromosome which affects fertility) may also lead to no sperm in the ejaculate.

Some cases of congenital bilateral absent of vas (the tube that carries the sperm) are associated with cystic fibrosis. In some infertile men, the absence of sperm in their ejaculate is due to retro-grade ejaculation (during orgasm, sperm enter the bladder and mix with urine, rather than are ejaculated into the vagina). This is a rare condition and accounts for less than 1% of male infertility, retrograde ejaculation may follow surgeries such as the removal of prostate and can be a side effect of certain drugs etc. As the sperm are normal, they may be recovered from the urine and used for insemination or IVF.

Male infertility due to poor sperm quantity or quality

This could be due to many factors such as hormone deficiency, varicocele (abnormal swollen blood vessels around the testicles), infection, drugs such as antidepressants, antihypertensive drugs (taken for high blood pressure), anabolic steroids used for body building and social drugs such as marijuana and cocaine, heavy smoking and excess alcohol. Other causes include frequent hot baths and saunas. Testicular cancer is also associated with an increased risk of impaired sperm production (it occurs in middle age men, whereby the risk is increased in men who have had a history of undescended testicles). Furthermore, antibodies to sperm (antisperm antibodies) adversely affect sperm production.

Male infertility due to impaired sperm fertilizing capacity

This could be due to defective acrosomes, abnormal lateral head movements of sperm, inability of sperm to bind to the zona pellucida, or excess free oxygen radicals in the semen.

Male infertility due to the inability to ejaculate into the vagina

This could be due to impotency, premature ejaculation, or the inability to ejaculate.

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