Male infertility may be caused by a number of factors including:
- Problems with sperm production
- Blockage of the sperm delivery system
- Antibodies against sperm
- Injury to the testicle
- Problems relating to hormone production
- Anatomical problems
- Presence of a varicose vein around the testicle (varicocele)
Past illnesses, infections, various diseases and medications can also cause infertility.
The development of normal, mature sperm is key in establishing male fertility and involves an interplay of several factors:
- An exchange of hormonal messages between the brain and the testicles
- A secretion of necessary reproductive hormones (testosterone) by Leydig cells and normal sperm development within Sertoli cells
- Normal transport of developing sperm from testicles to epididymis to vas deferens
The production of sperm is primarily regulated by three hormones:
- FSH (follicle-stimulating hormone)
- LH (luteinizing hormone)
In the male, pituitary hormones are responsible for maintaining the sperm production process. The pituitary gland, which is located at the base of the brain, secretes FSH and LH, the same hormones necessary for regulating the female's reproductive functions. FSH is responsible for stimulating sperm production in the testicles. LH stimulates the production of testosterone.
Under the influence of Sertoli cells and specific hormones, immature sperm cells develop through several stages and eventually become mature sperm cells, called spermatozoa. Spermatozoa are not yet motile. They must pass through the epididymis, where after 18–24 hours, they gain motility (movement). After acquiring the ability to move, mature sperm are stored in the vas deferens until ejaculation.
One of the most important parts of an infertility work-up for men is to identify if a sperm problem exists. This may influence further testing of the woman or may indicate the need for the man to undergo treatment while the woman undergoes further testing.
The semen analysis is the single most important test in the evaluation of a man's fertility. It provides information about a number of issues related to male fertility.
What affects the ability of sperm to fertilize an egg?
A semen analysis is the study of a freshly ejaculated semen sample. This analysis measures the number of sperm present in the ejaculate (sperm count) and checks the shape and size (morphology) of sperm and their motility.
The semen analysis is not an absolute test for fertility because it does not test certain important aspects of sperm function, such as whether sperm can actually penetrate the egg; however, it is very useful in initially determining if the cause of infertility is an obvious male factor.
Semen testing is performed using a fresh semen specimen. The specimen is obtained through masturbation and is collected in a container provided by the physician.
Semen for this analysis should not be obtained by interrupted intercourse or by use of an ordinary condom. Ordinary condoms contain substances that are toxic to sperm.
If religious or personal practices prohibit masturbation or if the patient feels uncomfortable, the physician may suggest using a special condom designed for specimen collection that does not damage sperm.
Feeling anxious about producing a specimen is common. Any questions or concerns should be discussed with a physician.
The information gathered during the semen analysis depends on proper collection of the specimen, as well as the skill of the technician or physician performing the test.
Before testing, a standard period of sexual abstinence is recommended. Often, this is two to three days or the "usual" number of days between intercourse for the couple. This helps the physician obtain an idea of what the normal seminal fluid exposure is for the female partner. Because sperm counts and quality can vary, at least two or three samples will usually be obtained to establish a baseline.
Evaluation of semen is based on standards established for fertile males. When a patient has values below these limits, a male factor does not necessarily exist, but the probability is significantly increased.
It is important to remember that, despite an overall low sperm count, men with high-quality sperm may still be fertile.
High quality sperm is defined as having a high percentage of motile sperm with good forward movement. Sperm motility appears to be one of the most important factors in determining the fertilizing capability of sperm.
The following standard parameters are commonly used to define a normal semen analysis:
If the results of a semen analysis warrant additional testing, there are several diagnostic tests that may be used to establish a diagnosis.
In addition to standard semen analysis, there are other tests of semen and sperm. These can help your doctor discover whether there is an infection, determine the size and shape of sperm and measure the ability of sperm to penetrate an egg.
White Blood Cells
During the semen evaluation, the presence of round cells will be assessed.
Although difficult to distinguish by routine microscopy, these cells can be either early sperm forms or inflammatory cells known as white blood cells (WBCs). Special stains or antibodies can be used to differentiate early sperm from white blood cells in the semen.
If pyospermia (an excess of these cells) is found, an evaluation for possible genital tract infections is undertaken because these cells can be associated with infection and/or inflammation.
These infections may contribute to sperm damage but are often easily treated.