Male InfertilityMale infertility is very common. About one in twenty men is sub fertile and a male factor is present in half of all infertile couples. About one third of all IVF procedures are performed for male factor infertility. For most men the discovery that they are infertile comes as a total surprise.
It must be remembered that the testis has two distinct roles. The first is to produce the male sex hormone, testosterone, which is important for providing sex drive, erections, strong muscles and basically giving a man a general feeling of well being. All these things can be described as virility. The second function of the testis is to produce millions of sperm everyday, a process which occurs inside the approximately 150 metres of fine tubes in each testis. For most infertile men it is only this process which is at fault and a reduced number or poor quality of sperm are produced.
Most infertile men produce low numbers of sperm which may also show both poor swimming ability (called motility) and be abnormally shaped. In such men, only a small number of normally shaped motile sperm are likely to swim up the woman's fallopian tube into the vicinity of the egg and even then may be unable to fertilise the egg.
Why does this problem develop? We now believe that most cases are genetic. In other words, these men are born without the genetic information which would allow sperm production to occur normally. At Monash University we have been researching this issue and find that small pieces of the Y, or so called male chromosome, missing in men with severe infertility. Presumably these missing pieces of genetic information are the cause for the poor sperm production. But we need much more research before we can point to particular genes. Without that knowledge no treatment for men to improve sperm counts is likely to become available. IVF techniques offer hope now as they require very much fewer normal sperm than does Nature.
In the remaining one third of infertile men, we can find a likely cause for their infertility including:
- Obstruction to the passage of sperm from the back of the testis to the outside can result from blockage or absence of the vas deferens. Common causes include, obviously, vasectomy, but any history of injury, and other surgery or sexually transmitted disease may be important.
- Men can make antibodies to their sperm following vasectomy or other trauma or infection. These antibodies are a common cause of infertility and prevent sperm swimming or sticking to the egg. Such antibodies can only be found using a special test on fresh sperm and is available only in a few laboratories including that at Monash IVF.
- The testis can be damaged by a wide number of treatments including chemotherapy or X-Ray therapy.
- Some men have difficulties obtaining an erection, or in ejaculating due to a wide range of problems such as diabetes, MS, or previous prostate surgery. In these cases sperm can be found and used for IVF.
- Rarely, a deficiency in the brain pituitary hormones may result in low sperm counts. Its detection is important as it is readily treated with hormone injections.
Finally there remains great controversy as to whether sperm counts have declined worldwide. The alleged change is quite small (about 15%) and no cause has been confidently identified.
In conclusion while the causes of infertility are uncertain in many men, certain conditions can be identified and treated. These facts make it essential that all infertile men have their situation thoroughly investigated.
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