What is the Normal Morphology of Sperm?
Sperm plays a vital role in conceiving a baby. To be able to fertilize an egg, semen must have an adequate concentration of sperm and the sperm must be properly shaped. The shape of sperm as seen under a microscope is termed as the morphology of sperm. Broadly speaking, there are two aspects to the sperm morphology; the size of the sperm and the shape of its head.
Normal Sperm Morphology
Under normal circumstances, sperm has an oval head and a long, slim tail. Some of the characteristics of normal sperm morphology are:
- A smooth rimmed head
- The width of sperm head: 2.5-3.5 micrometres
- Length of sperm: 5-6 micrometres
- 40-70% of the sperm’s head should encompass an acrosome tip. This contains the enzymes necessary for sperm to be able to penetrate through the membrane surrounding the egg.
- The head should not contain any large fluid-filled vacuoles
- There should be no more than 2 small fluid-filled vacuoles in the sperm head. This should take up less than 20% of the head.
- The section between the head and the tail should be the same length as the head but thinner than the head.
- The tail should be at least 45 micrometres long.
- The tail should be thinner than the sperm head and midsection.
- The tail should be free of defects.
How is Sperm Morphology Tested?
A fresh semen sample is needed for a sperm morphology test. The first step of this test is to take a semen sample on a glass slide and allow it to dry. This sample must contain at least 200 sperms. The technician then examines each individual sperm to see if it is normal or not. A man may be said to have normal sperm morphology if 4-14% of the sperm present in a semen sample is normal
It is usually recommended to take multiple sperm morphology tests for accurate assessment.
Can Sperm Morphology be Improved?
A low sperm morphology count does not mean that you cannot father children. However, there are ways to improve sperm morphology. Simple lifestyle changes such as regular exercise, maintaining a healthy body weight, wearing loose boxers instead of tight briefs and avoiding alcohol, cigarettes and drugs can help.
Sperm morphology reduces with age. Thus, in many cases, men may be advised to preserve their sperm at a young age. This ensures that healthy sperm is available at whatever age you plan to start a family.