In approximately 50% of infertile couples the male contributes at least partially to the cause of the problem. More than 90% of male infertility cases are due to low sperm counts, poor sperm quality, or both. The remaining cases of male infertility can be caused by a number of factors including anatomical problems, hormonal imbalances, and genetic defects.
Sperm abnormalities can be caused by a range of factors, including congenital birth defects, disease, chemical exposure, and lifestyle habits. Observing ejaculated semen with the naked eye will usually not contribute to making a decision whether a man is fertile or sterile. It is therefore only logical to perform a semen analysis as one of the first tests when an infertile couple is examined. Sperm abnormalities are categorised by whether they affect sperm count, sperm movement, or sperm shape. They include:
- Count: Anything below 10million sperm per mil or above 200million sperm per mil is considered abnormal. Azoospermia refers to the complete absence of sperm cells in the ejaculate, and accounts for 10 – 15% of cases of male infertility. Partial obstruction anywhere in the long passages through which sperm pass can reduce sperm counts. Sperm count varies widely over time, and temporary low counts are common. Therefore, a single test that reports a low count may not be a representative result.
- Motility: Sperm motility is the sperm’s ability to move. If movement is slow, not in a straight line, or both, the sperm have difficulty invading the cervical mucus or penetrating the hard outer shell of the egg. If 60% or more of sperm have normal motility, the sperm is at least average in quality. If less than 40% of sperm are able to move in a straight line, the condition is considered abnormal. Sperm that move sluggishly may have genetic or other defects that render them incapable of fertilising the egg. Poor sperm motility may be associated with DNA fragmentation and may increase the risk for passing on genetic diseases.
- Morphology: Morphology refers to shape and structure. Abnormally shaped sperm cannot fertilise an egg. About 60% of the sperm should be normal in size and shape for adequate fertility. The perfect sperm structure is an oval head and long tail. If less than this have an abnormal shape there is a problem as only the classic ‘acorn’ shaped sperm can penetrate an egg naturally
- Infection: White cells seen under the microscope when the sperm is being tested indicates an infection. The type of infection is isolated by doing a sperm culture for micro-organisms
- Positive Mar: Is a screening test done to assess what extend the sperm tends to clump together, preventing it being able to swim freely.
- Antibodies: These are confirmed by doing a blood test particularly if the mar is positive. Antibodies are present if there has been trauma to the testicles through an accident or operation
- Volume: If the volume is less than 2mls some of the components in the ejaculate might be missing.
- Retrograde Ejaculation: Retrograde ejaculation occurs when the muscles of the bladder wall do not function properly during orgasm and sperm are forced backward into the bladder instead of forward out of the urethra. Sperm quality is often impaired. Retrograde ejaculation can result from several conditions:
- Surgery to the lower part of the bladder or prostate (the most common cause of retrograde ejaculation)
- Diseases such as diabetes and multiple sclerosis
- Spinal cord injury or surgery
- Medications such as alpha blockers used for enlarged prostate glands, tranquilisers, certain antipsychotics, or blood pressure medications may also cause temporary retrograde ejaculation.