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Testing for Fertility in Men part two

Testing for Fertility in Men part two

Read Testing for Fertility in Men first.

The semen liquefaction

Semen analysis should begin with a simple inspection soon after liquefaction. This is done preferably at 30 minutes after ejaculation but no longer than one hour to prevent dehydration or changes in temperature from affecting semen quality. Normal liquefied semen samples may contain jelly-like granules (gelatinous bodies) which do not liquefy. These do not appear to have any clinical significance. Poor liquefaction means the sperm may not be released to fertilize the egg.

The following are the normal settings

Semen volume

Semen Quantity

The sperm count is performed by careful analysis under a microscope. In a normal setting, a fertile male ejaculates about 60 million or more sperm per milliliter. How ever, there is a range of 20 to 150 million sperm per milliliter to be within the normal.

Semen sugar

Fructose is present in large quantities in semen and is the main energy source for sperm. Fructose is produced only by the seminal vesicles. In conditions such as bilateral congenital absence of the vas, where there is absent seminal vesicles, the fructose in the ejaculate will be absent or very low. When there are no sperm counts in the ejaculate, this may indicate a problem. During normal sperm production, fructose is added to the semen by the epididymis.

Therefore, if fructose is not present, there may be a blockage along the male’s reproductive tract that is preventing the sperm from getting into the ejaculate. If fructose is present in the semen, this suggests that there may be a problem in the testicles’ ability to manufacture sperm. Even if the sperm count is normal, the sperm is not necessarily of good quality.

The pH of semen

The pH of seminal fluid lies between 7.2 and 8.0 and is measured in fresh samples of semen. It tends to fall as the sample ages. The pH of semen can occasionally be of value diagnostically to the doctor. Because of its high protein content, semen is a very effective buffer and it is difficult to alter its pH. However, severe infection particularly that of the prostate and seminal vesicles can increase the acidity of semen and a low pH may be helpful in making such a diagnosis. In men with bilateral congenital absence of the vas deferens where there is little production of and the pH is often reduced.

The Shape of sperm

A sperm that is shaped normally is more likely to fertilize the egg than one with a structural abnormality. In a normal setting, one must have at least 60 percent normally shaped sperm in a semen sample to be fertile. Abnormal sperm typically cannot move normally or penetrate an egg. An oval head is deemed to be normal but many shape and size variations can be seen in an ejaculate, and these include large, small or tapering heads.

Sperm Movement

For the sperm to reach and penetrate the eggs, the speed and direction of the sperm is important. In the normal setting, when the sperm that have good motility, they can move through a woman’s reproductive tract at the rate of two inches per hour. At least 50 percent of the ejaculated sperm should have forward movement.

The Hamster egg penetration test (HEPT)

This is the test of the sperm’s ability to penetrate hamster eggs and is recommended when the male partner has a normal semen analysis and the woman has no obvious fertility problem, but pregnancy is still not occurring. In 1976, Yanagamachi and colleagues discovered that zona free hamster eggs could be penetrated by human sperm (Yanagamachi et al.1976), and Rogers and colleagues went on to develop this phenomenon as a test to predict the ability of a human sperm to fertilize an egg (Rogers et al.1979).This test is also performed prior to IVF to see if that technology will be successful for the couple. Essentially, the hamster test is a trial run of IVF but uses hamster eggs instead of a woman’s. The test is 90 % accurate.

Antisperm Antibody (ASA) test

Anti-sperm antibodies (ASAs) in semen belong almost exclusively to two immunoglobulin classes: IgA and IgG. IgM antibodies, because of their larger size, are rarely found in semen. Both classes can be detected on sperm cells or in biological fluids in related screening tests. When a man develops such antibodies against his own sperm, the antibodies attach themselves to the sperm’s surface and adversely affect the sperm’s movement and ability to fertilize an egg. It has been theorized that the antibodies occur when their sperm come into contact with their own blood such as during injuries or vasectomy. The body then develops the antibodies since sperm in blood are identified as foreign proteins which must be eliminated.

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