Sperm morphology is a sub title of semen analysis laboratory test. Semen analysis test is done to examine the semen and sperm characteristics for diagnosis of male type infertility. Semen analysis test evaluates several features of semen and sperm like;
- Semen volume
- Sperm concentration
- Sperm count
- Semen pH
- Sperm morphology
- Sperm motility
- Semen appearance
- Semen WBC count
- Semen liquefaction time
Sperm morphology is an important factor about fertility but morphology is not a single cause for infertility. Sperm count, sperm motility and other factors are important, also the piece of the sperm cell that has abnormality is important. Different sperm cell parts have different functions so sperm cells are examined to understand which part of the sperm has abnormalities.
Sperm cell parts
- Head ; has the acrosome and nucleus
- Neck ; centrioles
- Middle piece ; contains mithocondria for energy production
- Tail ( flagellum) for motility
- Sperm head
Sperm head is spheric shape and contains 2 important parts; nucleus and acrosome. Sperm head contains genetic material-DNA. Sperm nucleus contains genes and 23 chromosomes which are responsible for baby creation and growth. Acrosome contains enzymes that destroys the egg membrane and helps sperm cell to penetrate and fertilize the egg.
If sperm DNA is damaged, fertilization chance is decreased. DNA damage is found high in sperm cells which have abnormal morphology. Also DNA damage may be found in sperm cells which have normal morphology. This means we can’t exactly say that there is DNA damage or not just only looking to sperm morphology. Sperm morphology may be found low but if there is no DNA damage you may have pregnancy chance.
Sperm needs acrosome to break down the egg membrane, if sperm cell does not have acrosome bag , pregnancy chance is decreased in natural ways. In globozoospermia condition , sperm head has a round shape and has no acrosome so sperm cell can’t fertilize the egg. Sometimes acrosome bag is opened early and sperm can’t penetrate the egg, this is an another infertility cause.
Sperm morphology- sperm head abnormalities
There are different types of sperm head abnormalities;
- Large head; macrocephalic
- Small head; microcephalic
- Double head or duplicate head
- Teardrop head
- Small acrosome
- No acrosome
- Elongated head
- Pin head