Sperm Morphology

• What is sperm morphology?
• What does healthy sperm look like?
• What does abnormal sperm look like?
• Does sperm morphology affect fertility?
• How is sperm morphology tested?
• How to interpret semen analysis results
• Can sperm morphology be improved?
• When to seek medical advice

Sperm morphology is the term used to describe the size, shape and structure of sperm cells. It is also used to refer to the percentage of sperm cells in a semen sample with a healthy shape. Sperm morphology impacts their ability to swim effectively and fertilise an egg, making it an important determinant of sperm quality.

Healthy sperm resemble tadpoles, with a single smooth, oval head, a neat midpiece and a single long and relatively straight tail. 

• Head – an oval shape with a smooth surface and a pointed “cap” (acrosome). The head contains genetic material and is essential for egg fertilisation.
• Midpiece – regularly shaped with no bulges or deformities. The midpiece or “neck” plays an important role in energy production.
• Tail – a long, whip-like tail with no coils or splits. The tail is responsible for propelling the sperm cell forward.

Abnormal sperm typically feature deformities in one or more parts of the cell.

• Head – common irregularities include a completely round or overly pointy shape, bulges in the surface, or split or doubled heads.
• Midpiece – common defects include a flared shape or bulges in the midpiece.
• Tail – common deformities include coils and kinks or split, doubled or short tails.

What causes abnormal sperm morphology?

Abnormal sperm morphology can be caused by:

• Medical conditions – such as varicocele, diabetes and semen and testicular infections.
• Medical treatments and procedures – abnormal sperm morphology can result as a side effect of radiation treatment, chemotherapy or a vasectomy.
• Genetic alterations – genetic mutations and deletions can cause abnormalities, as can certain genetic conditions, such as Klinefelter syndrome.
• Lifestyle and environmental factors – harmful habits such as smoking can cause abnormalities, as can environmental factors, like exposure to toxins or hot conditions that cause testicular overheating.

Sperm morphology can impact male infertility, but it is not the only factor determining your ability to conceive. Semen analysis is used to determine sperm quality, and it also takes into account:

• Sperm count (concentration) – the number of sperm cells per millilitre (mL) of semen.
• Sperm motility – how efficiently sperm move through the female reproductive tract.
• Semen volume – the amount of semen ejaculated in mL. 

Semen analysis will consider all of these factors when assessing sperm quality. 

Can you get pregnant with low morphology?

Yes, there is still a chance that you can conceive via sexual intercourse with low sperm morphology. Sperm morphology is a sliding scale. While a 3.9% morphology rating may technically qualify as teratospermia, you would have a similar chance of conceiving as someone with a healthy measurement of 4%. Though the likelihood of conceiving drops as morphology decreases, and if there are other semen quality concerns present, it may still be possible to conceive. 

If you cannot conceive with your own sperm, there are other options. Fertility treatments using donor sperm are a common path to parenthood for couples experiencing male fertility challenges.

Sperm morphology is measured through semen analysis, a laboratory test that measures semen volume and sperm count, motility and morphology to evaluate overall sperm quality. Fertility specialists assess semen samples in a lab, under a microscope, to measure these factors.

Your fertility clinic or healthcare professional will typically help you interpret your semen analysis results and provide support and additional information, if required. The following figures are the parameters for healthy semen analysis results, as determined by the WHO.

If you have any questions regarding your sperm analysis results, we recommend discussing them with a healthcare professional.

There is no guaranteed way to improve sperm morphology, but making lifestyle changes may have a positive impact. Key steps include:

• Eat a healthy diet – a Mediterranean diet rich in antioxidants and Omega-3 can reduce oxidative stress and potentially improve sperm morphology.
• Limit harmful habits – quitting smoking and limiting alcohol intake have a positive impact on sperm quality.
• Maintain a healthy weight – excess body fat can affect hormone regulation, which can be detrimental to sperm production.
• Avoid exposure to toxins – pollutants, pesticides and other toxins can impact sperm morphology and should be avoided.
• Keep the scrotum cool – limit prolonged exposure to high temperatures, such as sitting for long periods with a laptop on the lap or spending too much time in saunas or hot tubs.

As it takes between 75 and 90 days to produce and mature new sperm cells, you will need to make and maintain these lifestyle changes for at least three months for them to have an effect.

Aspiring parents who are 35 or younger are advised to try conceiving via regular, unprotected sexual intercourse for at least 12 months before seeing a fertility specialist. 

Aspiring parents who are over 35 should try to conceive via sexual intercourse for six months before seeing a fertility specialist. 

You may also want to see a fertility specialist if you notice any of the following signs:

• Swelling, pain or lumps in the testicles
• Erectile dysfunction or ejaculation problems
• Reduced libido
• Changes in breast or testicle size.

Finally, it is a good idea to seek a medical professional if you are concerned about your fertility or are concerned about changes in sexual function or feeling or your genitals.