Investigations of male infertilityOften the infertile man is entirely healthy but for some reason produces poor quality sperm. However some men have serious medical problems such as a low male sex hormone, testosterone, level.
It is therefore very important that men in infertile relationships see a doctor trained in reproductive medicine. Previous fertility, genital surgery or infections, undescended testes and certain systemic diseases are of importance. The adequacy of sexual development, the size and texture of the testes and normality of the tubes attached to the back of the testes are assessed.
The most important test is the semen analysis which requires a great deal of expertise to comply with the high standards prescribed by the World Health Organisation. The laboratories of Monash IVF in Melbourne and Queensland are two of only a few meeting these criteria.
Semen quality varies widely between men. Even for a particular man a minimum of two sperm counts at least three weeks apart need to be taken to give a true indication of his sperm quality. The test is performed after two to five days of sexual abstinence. Ideally the laboratory provides an appropriate collection room so avoiding changes in temperature during the transport of samples to the laboratory.
A sperm count greater than 20 million/ml is considered normal, however the average for the population is about 60 million and some men have a sperm count of above 200 million/ml. Sperm counts between five and 20 million do not necessarily indicate a severe infertility problem. The ability of sperm to swim is termed motility. Normally greater than fifty per cent of sperm show some motility. Markedly reduced motility problems can greatly reduce fertility. The sperm shape, termed morphology, is an important predictor of fertility and the accurate assessment of this feature requires great skill.
Sperm antibodies are an important cause of infertility as they reduce the sperm's motility and ability to stick to the egg. They can be readily detected on fresh sperm at the time of semen analysis and are an essential initial test performed in the better laboratory. A complementary test is the sperm mucus interaction test which examines the ability of sperm to swim through mucus.
Blood hormone tests are also frequently performed. Poor testicular function can reduce testosterone levels which in turn impairs sex drive and energy levels. The FSH (Follicle Stimulating Hormone) test gives an indication of the amount of sperm being produced. In normal men or those with a blockage of sperm outflow, FSH levels are normal. However when the testicle is severely damaged, and few or any sperm are being produced, FSH level rises progressively.
A zero sperm count may be due to either blockage in the tubes or to the failure of sperm production. A testicular biopsy, often using a fine needle under local anaesthesia, with microscopic examination readily clarifies whether sperm are present in the testis. In some cases of blockage, further tests such as ultrasound of the prostate and bladder region is performed.
Finally in men with very poor sperm production who are considering using the new single sperm microinjection procedure, there are two genetic tests which are frequently recommended to help understand why they have this problem and to assess the risk to their future children. One involves counting the number of chromosomes and the other looks for damage to the male, or Y, chromosome, which is important in controlling sperm production.
In conclusion, thorough clinical assessment of the man and the performance of a range of specialised hormone and sperm tests are needed to fully evaluate the infertile man.
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