The size and shape of male’s sperm is referred to as sperm morphology. It is one of the important factors in deciding the fertility of a man, however not the only factor affecting infertility. Since, fertility is usually measured by sperm concentration, motility, vitality and morphology. A microscopic examination is sufficient to identify the morphology of the sperm. It is common possibility that every man produces an average of 4% of abnormal sperms. If the rate is above this in 1-1.5 ml of semen sample, the impediment to pregnancy increases.
The normal sperm morphology has the following attributes:
• A oval-shaped head with smooth surface, that is 5-6 micrometers long and 2.5-3.5 micrometers wide and a long tail
• A well-defined acrosome (head ) that covers 40% to 70% of the sperm head
• No visible abnormality of neck, mid piece, or tail
Morphology and fertility:
Any abnormality in one of the parts of the sperm can prove to be the reason why a man is unable to father a child. It is also called teratospermia or teratozoospermia. Some of them are:
• A defect in the tail affects its motility, since the whip-like motion of the tail is what propels the sperm towards the ovary within the uterus, any defect as shown above might prevent the movement of the sperm towards the egg.
• The egg is encapsulated in a layer of glycoprotein called Zona Pellucida, which acts as the first line quality check of the sperm. Only a sperm with proper shape and size is allowed to penetrate within. Thus, a defect in head prevents it from penetrating the egg thus hindering fertilization.
• Some studies suggest that, there might be genetic defects as well due to the variation in the shape/size of head of the sperm, which in turn affects the way the traits of the new born are determined.