Sperm Mobility

Did you know that a couple's inability to get pregnant is just as likely to be the result of male infertility as female infertility? Among the contributing factors to male infertility are problems with a man's sperm, also known as the sperm quality. Among the sperm abnormalities that can occur are: the absence of sperm (rare), low sperm count, abnormal sperm shape, and poor sperm mobility or motility.

What is Sperm Mobility?

Low sperm quality, a condition technically called Dysspermia, is determined by two elements: the sperm's morphology (shape and structure) and the sperm's motility, or ability to move. The latter is affected by both a sperm's speed and its quality of movement. If sperm motion is slow and/or not in a straight line, sperm may not be able to penetrate the cervix mucous or the shell of an egg. Sperm with such sluggish movements may be incapable of fertilizing a woman's egg.

If 60% or more of a man's sperm have normal motility, the sperm are deemed to be of average quality. If less than 40% of a man's sperm have good motility, this is considered abnormal. Note that other causes of poor sperm motility are genetic or other defects.

How to Determine Sperm Mobility

Motility is determined by a ranking system called "motility grade." In this system, the mobility of sperm is divided into four categories or grades:

Grade 1: Sperm make little forward progress or are immotile and fail to move at all.

Grade 2: Sperm move very slowly, or sperm in this class move their tails but do not progress forward. This condition is called "non-progressive motility."

Grade 3: Also known as "non-linear motility," sperm move forward but travel in a curved or crooked fashion. This condition is sometimes denoted as "motility b."

Grade 4: Sperm have progressive motility. These sperm are strong, swim fast, and swim in a straight line. This stage is also denoted as "motility a."

Testing for Sperm Mobility

Sperm motility can be diagnosed via a semen analysis wherein a man's semen is sent to a laboratory to be analyzed. A semen analysis provides the following information:

•· Total number of sperm in the sample (count)

•· Number of sperm per milliliter of semen (concentration)

•· Amount of semen produced (volume)

•· Percentage of moving sperm (motility)

•· Shape of sperm (morphology)

Note that a semen analysis should be repeated at least three times over several months.

Anytime infertility is suspected, it is advisable to perform a semen analysis. A couple's failure to get pregnant is most often due not to one but to a number of factors, among them the quality of a man's sperm. The sooner the barriers to fertility are identified, the sooner appropriate treatments or interventions can commence. The good news is that male infertility is usually highly treatable!

Testing for sperm motility can be particularly valuable in predicting the success of artificial insemination techniques like intracytoplasmic sperm injection (ICSI). Men with poor sperm motility might be excellent candidates for this procedure, in which the sperm is inserted directly into the egg. In this case, sperm motility plays a minimal role.

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