When there are mobility problems in the sperm, we speak in medical terms of asthenozoospermia, colloquially also known as slow or "lazy" sperm.
The higher the percentage of immobile or slow spermatozoa, the more difficult it is to achieve a pregnancy naturally. For this reason, in the majority of cases in which there is an alteration in the mobility of the spermatozoa, which implies that the spermatozoa are going to have greater difficulty in traveling all the way to reach the egg and fertilize it, it is going to be necessary to resort to some kind of assisted reproduction technique.
The seminogram is the test used to evaluate the characteristics of the semen and assesses three parameters: concentration (number of spermatozoa per ml), motility, and morphology (percentage of spermatozoa with normal shapes).
Specifically, within motility, three types can be established:
- Motility type a
- progressive, fast or rectilinear.
- Motility type b
- Slow progressive.
- Motility type c
- without displacement, i.e. the spermatozoa vibrate.
- Motility type d
- static or immobile spermatozoa.
Asthenozoospermia, therefore, is a very common cause of sterility in males.
As far as possible treatments are concerned, artificial insemination would not be indicated when the motility is very low, because the sperm would not be able to make the normal journey and fertilize the egg. For this reason, the treatment of choice in most cases of moderate-severe asthenozoospermia would be in vitro fertilization (IVF), which can be:
- Conventional IVF
- a large number of spermatozoa are brought into contact with the egg in a plate and in the incubator so that fertilization occurs naturally. This technique is only indicated if the decrease in motility is slight-moderate.
- it is the biologist who introduces the selected spermatozoon inside the egg, so it is not necessary for it to move.