In
the past it was considered necessary to address the reproductive
function of a man only if his sperm count was found to be
low. However, It is now known that count is not the only factor
in impaired fertility cases, motility and morphology also
play a major role in a man’s ability to fertilize.
A
man with fewer than 5 million sperm per milliliter of semen
is often infertile. A sperm count below 20 million is considered
low. In these cases the men might be sub-fertile or infertile.
However, it should be understood that a man can be sub-fertile
even if he has a normal sperm count of between 20 and 250 million
sperm per milliliter of semen.
The sperm’s ability to move is referred to as motility.
The most successful sperm are those that are able to move
forwards rapidly. Rapid motion forward is defined as a sperm
that is able to travel at least half its length in one second.
Often times, sperm are found to lack this essential aspect
of motility and they end up swimming slowly or in the wrong
direction, some even swim in circles. The sperm’s ability
to move correctly is directly linked to its shape.
The
morphology of sperm is the third key factor in evaluating the
role of abnormal sperm cells. A normal sperm is made up of a
head, a mid piece and a tail. A normal head is oval in shape
and can be easily distinguished from the mid piece. The mid
piece should have approximately half to three quarters the area
of the head. And the tail should be around four or five times
the combined length of the head and mid piece. When variation
in just one of these areas occurs, a sperm’s chance for
success is greatly reduced as a miss-shapen head or a deformed
tail can cause the sperm to be a weak swimmer or to be incapable
of maintaining a straight path.
