Asthenic means Weak. Asthenozoospermia is a condition where the sperms have reduced motility (movement) compared to healthy ones. Some men have 100% immotile sperms and that happens to 1 in 5000 men.
It is this inability of the sperm to move efficiently inside a woman’s body which is vital to reach the egg and cause progency. Yes, your guess is correct, asthenozoospermia causes Infertility in men. The motile and healthy sperm needs to move through the woman’s reproductive tract to fertilise the egg for it to result in a pregnancy.
Men are diagnosed with low sperm motility when less than 40 per cent of the sperms can move efficiently. For the sperm to get through the cervical mucus to fertilize a woman’s egg it needs to have a progressive motility of at least 25 micrometres per second, anything less than that results in low sperm motility.
There are different types of sperm motility issues, which include; slow or sluggish progressive motility, non-progressive motility (less than 5 micrometres) and no motility. Progressive motility is where the sperms move linearly. Non progressive motility may be either when the sperms move sluggishly or go around and around in the same place.