Sperm Morphology means the shape of the Sperm and as you can read below is very important for a pregnancy. Sperm head (shape of the head, presence of acrosome)-neck and tail. Head anomalies constitute the most important defects in sperm morphology.
One of the most important indicators of sperm quality is its shape. Among the parameters evaluated in semen analysis, sperm motility and sperm morphology give the most important information about the fertilization potential of the sperm sample. The relationship between sperm morphology and success of eggs fertilising into embryos has been researched and proven to be important. There are 2 common methods used in the evaluation of sperm morphology; WHO criteria and Kruger’s strict criteria. Kruger’s exact criteria are the most commonly used method in our centre, as it provides a much more detailed examination of the sperm morphology.
When evaluating the morphology of Sperm, at least 100 sperm cells are analysed within semen analysis. After a special staining (Spermac), the shape (morphology) and characteristics of the sperm are examined and the fertility (fertilisation) capacity of the sperm sample can be determined. The dye stains the sperm nucleus red, and the acrosome, neck and tail green. More than 4% of the sperm in the semen should have a normal shape. If the number of sperm is of a normal shape and is less than 4%, this may adversely affect the success of IVF. Less than 4% of the normal sperm count is expressed as possible “teratozoospermia”. In the lower distribution, the anomalies of the sperm head are divided into severe and mild. In our centre, it is considered important that severe sperm head anomalies are seen in more than 80% according to Kruger criteria. It is important to explain and discuss this with couples who are undergoing fertility problems and according to the results of the semen analysis a plan forward should be discussed.
Sperm production (spermatogenesis) is a complex and sensitive process, any disruptions that can occur in the different stages of production of sperm can be dependent on the genetic structure, internal environment of the body or external factors that may cause teratozoospermia.
Normal Sperm Morphology: The sperm cell consists of three parts: head, middle part (neck) and tail. The roles of each part are detailed below:
Acrosome: Is important for fertilising the egg and is a unique membranous organelle located over the anterior part of the sperm nucleus
Head: Healthily transports the DNA within the Sperm;
Neck: Energy production by the content of mitochondria and therefore the movement of the sperm
Tail: Important for Sperm movement
The head is the most important part of the fertilisation process. A normal sperm should have a head length of 4 to 5 µm, a width of 2.5 to 3.5 µm, and a head length/width ratio of 1.50-1.75. The middle part should be cylindrical, 0.5 µm-1µm thick, 7-8 µm long and flat to the head. The tail should be slightly thinner than the middle, without curls, well-formed and approximately 40-50 µm in length.
The absence of the acrosome in the sperm head is called globozoospermia. In this case, the ability of the sperm to fertilize the egg decreases. In IVF treatment, the procedures of this patient group require a more special approach and experienced team.