This is when the sperm “motility” is reduced. Motility is one of the important paraments of sperm quality, therefore low motility mean low quality of sperms and reduced chance of natural conception. If the count is quite high , the effect can be negated as the absolute number of motile sperm can be normal. The absolute number of the motile sperm is called Sperm Motility Index which is more important than only the percentage of motile sperm. The Motility index can be calculated by percentage of motile sperms (% moving forward) X sperm concentration. This is more correlated with chance of pregnancy rather than the percentage of motile sperms.
