Sperm Morphology - Basics And Overview

What Is Sperm Morphology?

Sperm morphology refers to the appearance or form of the sperm i.e size and shape. Sperm Morphology is said to be a very strong indicator of a man’s testicular health.¹ Multiple aspects are taken into consideration while evaluating sperm’s morphology, including its head, midpiece, tail, and the presence of cytoplasmic droplets. (A small portion of cytoplasm found in the sperm).² As per WHO standards, a sample should have about 4-39% of normally shaped sperms.³

How Does A Normal Sperm Look?

A sperm normally possess the following characteristics- ⁴ 

• Head: A smooth and oval shaped structure with a size less than a needle point (5-6 micrometers in length; 2.5-3.5 micrometers in width). 
• Acrosome: A well defined cap-like structure covering 40-70% of the head. It is a membrane that contains enzymes which are able to penetrate an egg’s membrane.⁵
• Midpiece: A thin structure between the head and the tail 
• Tail: Also known as the neck, it is said to be a defect-free structure thinner than the midpiece. It is said to be around 50 micrometers in length.⁵

A normal sperm will have no visible abnormalities in any of the above structures. Also, there are no fluid droplets (cytoplasmic droplets) in the head of the sperm which are larger than one-half the size of the sperm head. 

Importance Of Morphology  

Assessment of sperm morphology has been described by some authors as a good indicator of male fertility. ⁶ It is understood that there is no hindrance in sperm production and development when no defects arise in a sperm’s overall shape and size. Occurence of a defect in its morphology indicates disturbance in the process, which inturn may interfere with conception thereby affecting fertility. 

Having abnormally shaped sperm in higher amounts can be associated with infertility as per some studies. It can also be linked with other irregularities of the semen such as low sperm count or motility. On the other hand, Men with abnormally shaped sperms may also have no trouble achieving a pregnancy.⁴

Factors Affecting Morphology Of Sperm 

• Age: With age, morphology of sperm is found to decrease. Studies show a decline in normal sperm morphology of 0.2% to 0.9% per year of age.^{5 6}
• Stress: Work and life stress factors are found to be associated with sperm morphology. ^{6 7}
• Recreational drugs: Cocaine, an highly addictive and strong stimulant is associated with a higher fraction of sperm with abnormal sperm morphology.⁶
• Obesity: Men who are overweight were found to have a higher percentage of sperms with abnormal sperm morphology.⁶
• Smoking: Cigarette smoking has been found to have a negative impact on morphology due to reduced testosterone levels and zinc concentrations.⁷
• Alcohol: Studies have reported that alcohol intake has a detrimental effect on morphology of sperm.⁶
• Diabetes Mellitus: Studies have shown association of Diabetes Mellitus with abnormal morphology such as double head, round and elongated spermatids and cytoplasmic mid- and tail pieces.⁸
• Metabolic syndrome: It is a complex disorder which has a plethora of negative effects on sperm health, including morphology.⁸
• Abstinence period: With the increase in duration of abstinence period, sperm morphology is found to decline.⁹
• Environmental factors: Studies have shown that exposure to air pollutants, toxins and heavy metals negatively affect the sperm morphology ¹⁰

Sperm Morphology And Fertility 

• Teratozoospermia

Fact: Teratozoospermia is a sperm disorder characterized by aberrant sperm morphology (normal morphology <4%). In this condition, defects can be caused in the head, midpiece, and/or tail of the sperm.¹¹ 

Implication: In all situations, teratozoospermia is linked to male infertility since the sperm are unable to reach the egg due to their aberrant form. The causes may be varied and sometimes difficult to determine. If the cause is related to certain unhealthy habits, it is possible to improve sperm health by taking the required steps. In case of the severe form finding a treatment option is required with proper medical assistance. For Assisted Reproductive Technology (ART) either IUI, IVF or ICSI can be considered based on the total motile count. Teratozoospermia may also have a genetic linkage wherein certain genes may be responsible for the occurence of the condition. Take up InferGenes test, an at-home genetic test that helps analyze the genetic root cause of the condition. 

• Macrozoospermia 

Fact: Macrozoospermia is characterized by abnormal sperm. In affected males, almost all sperm cells have abnormally large and misshapen heads.¹² 

Implication: In men with macrozoospermia, the sperm cell head contains extra chromosomes, usually four copies of each instead of the usual one. This additional genetic material accounts for the larger head size of the sperm cell. Additionally, instead of having one tail (flagellum) per sperm cell, affected sperm have multiple flagella, most often four. If one of these aberrant sperm cells joins with an egg cell, the embryo will not develop or the pregnancy will end in miscarriage. Finding the right treatment option is required with proper medical assistance. Macrozoospermia may also have a genetic linkage wherein certain genes may be responsible for the occurence of the condition. Take up InferGenes test, an at-home genetic test that helps analyze the genetic root cause of the condition.

• Globozoospermia

Fact: Globozoospermia is a condition characterized by the presence of abnormal round-headed sperms with the absence of a structure called acrosome. Presence of these abnormal sperms may lead to an inability to father a child. ^13,14

Implication: Normal sperms have an oval-shaped head with a cap-like covering called Acrosome. It is an organelle overlying the head of the sperm that is required for fertilization. Acrosomes contain enzymes that break down the egg cell's outer membrane, allowing sperm to fertilize the egg. In the occurrence of globozoospermia either the acrosome might be missing or severely underdeveloped in the sperm. Other circumstances might include the sperm head having a round shape or the midpiece of the sperm also being abnormal. Genetic mutations are the most common cause of globozoospermia. In roughly 70% of men with this condition, DPY19L2 gene is found to be mutated.¹³ Other gene mutations are also likely to cause globozoospermia. Take up InferGenes test, an at-home genetic test that helps analyze the genetic root cause of the condition. Males who are affected by this condition may benefit and achieve pregnancy from Assisted Reproductive Techniques (ART). In this case, Intracytoplasmic Sperm Injection (ICSI) is the suggested technique. ^13,14

Ways To Improve Your Sperm Health

1. Avoid Smoking

Semen parameters and sperm function test results are lower in smokers than in nonsmokers. Most of these effects are usually dose-dependent.¹⁵

2. Reduce Alcohol Consumption And Drug Use

Drugs (steroids, marijuana) and alcohol can negatively impact sperm health leading to abnormally shaped sperm, decreased sperm motility and/or decreased sperm production. ¹⁶  

3. Maintain Healthy Weight

There exists a clear link between obesity and reduced sperm production. Overweight men who want to improve their fertility should maintain a healthy weight. ¹⁷ 

4. Practice Safe Sex

Sexually transmitted infections (STIs) are a leading cause of infertility. Having safe sex today may increase your chances of conception in the future.¹⁶

5. Reduce Heat Exposure

Men who are exposed to prolonged high heat (like hot tubs or using laptops on your lap)  can affect your fertility by lowering sperm production. ^{16 17}

6. Avoid Commercial Lubricants

Some commercial lubricants/substances used for lubrication should be avoided during the fertile period. This may reduce sperm movement and their ability to survive.¹⁷

7. Choose The Right Clothing

Men who wear heat retaining clothes experience decreased sperm production ¹⁶. As per studies wearing brief underwear may decrease sperm quality.¹⁷

8. Manage Your Stress

Many stress-reducing techniques like Meditation, Yoga, Music, Therapies etc., can effectively keep stress at bay.¹⁸

How Can You Check Sperm Morphology? 

You can get a semen analysis done. Semen analysis evaluates the characteristics of a male's semen and the sperm contained therein. 

As a result of social stigma in some parts of the world, many men refrain from getting their semen tested. While in-clinic semen analysis was the only choice previously, there is now an at-home option that delivers concrete data.