Sperm Motility: Causes of Low Motility & Treatment
Sperm Motility: What It Means and How It Affects Male Fertility
Having enough sperm is only part of male fertility.
For sperm to contribute to conception, they also need to be capable of moving effectively.
This characteristic is known as sperm motility.
A man can have a reasonable sperm count but still experience fertility difficulties if a large proportion of his sperm have poor movement.
Low sperm motility is sometimes referred to as asthenozoospermia.
The good news is that reduced motility does not automatically mean that natural conception is impossible. The significance of the result depends on the severity of the abnormality, the sperm count, morphology and the fertility of both partners.
What Is Sperm Motility?
Sperm motility describes the ability of sperm to move.
During natural conception, sperm need to travel through the female reproductive tract toward the egg.
Effective movement is therefore an important part of sperm function.
A semen analysis usually evaluates whether sperm are:
Moving progressively
Moving without effective forward progression
Completely immotile
The exact reporting system can vary between laboratories.
What Is Progressive Sperm Motility?
Progressive motility refers to sperm that move forward in a meaningful direction.
These sperm are more capable of travelling through the reproductive tract than sperm that move without making forward progress.
Progressive motility is therefore an important parameter when assessing semen quality.
What Is Non-Progressive Motility?
Non-progressively motile sperm are moving but do not move forward effectively.
They may move in place or follow a very limited path.
Although movement is present, it is less useful for natural sperm transport.
This is why semen analysis distinguishes between different types of movement rather than simply reporting whether sperm are "moving" or "not moving."
What Does Immotile Sperm Mean?
Immotile sperm do not demonstrate movement during the assessment.
A certain proportion of immotile sperm can be present in a semen sample.
The concern arises when the proportion of immotile sperm is unusually high.
When motility is severely reduced, further assessment may be needed to determine whether the sperm are alive but immotile or whether they are non-viable.
What Is Asthenozoospermia?
Asthenozoospermia is the medical term used to describe reduced sperm motility.
It may occur alone or together with other semen abnormalities.
For example, a man may have:
Low sperm count and low motility
Normal sperm count and low motility
Low motility and abnormal morphology
The combination of abnormalities can provide more information than any single semen parameter.
Can Low Sperm Motility Cause Infertility?
Yes.
Reduced motility can make it more difficult for sperm to reach and fertilise the egg.
However, low motility does not mean that pregnancy is impossible.
The impact depends on:
Number of sperm
Percentage of progressively motile sperm
Sperm morphology
Female partner's fertility
Duration of infertility
Other reproductive factors
A specialist should interpret the result as part of the complete fertility assessment.
What Causes Low Sperm Motility?
There are many possible causes of reduced sperm motility.
These include:
Varicocele
Testicular disorders
Previous infections
Hormonal abnormalities
Genetic conditions
Oxidative stress
Smoking
Obesity
Certain medications
Heat exposure
Testosterone or anabolic steroid use
Advanced age
Lifestyle factors
Unknown causes
Sometimes no single cause can be identified.
Can Varicocele Affect Sperm Motility?
Yes.
A varicocele can affect several aspects of sperm quality, including motility.
The mechanisms may involve changes in:
Testicular temperature
Oxidative stress
Testicular blood flow
Testicular function
However, the presence of a varicocele does not automatically mean that surgery is necessary.
Treatment should be considered according to the clinical findings and the man's fertility situation.
Can Hormonal Problems Affect Sperm Motility?
Hormones are essential for normal spermatogenesis.
Disorders affecting testosterone, FSH or LH can interfere with sperm production and function.
For example, men with hypogonadotropic hypogonadism may have markedly impaired sperm production because the testicles are not receiving adequate hormonal stimulation.
In selected patients, correcting the hormonal disorder can improve reproductive function.
Can Testosterone Therapy Reduce Sperm Motility?
Testosterone therapy can suppress sperm production.
When external testosterone reduces FSH and LH, the testicles receive less hormonal stimulation.
This can lead to:
Reduced sperm concentration
Reduced sperm production
Severe oligospermia
Azoospermia
Changes in motility may occur alongside these reductions.
Therefore, testosterone should not be used as a treatment for low sperm motility in men trying to conceive.
Can Infection Affect Sperm Motility?
Certain infections and inflammatory conditions involving the reproductive tract can affect sperm function.
Inflammation may alter the environment in which sperm develop or travel.
Depending on the underlying condition, a specialist may investigate:
Previous sexually transmitted infections
Epididymitis
Orchitis
Prostatitis
Other genitourinary infections
Treatment depends on the diagnosis.
Can Fever Reduce Sperm Motility?
A significant fever can temporarily affect spermatogenesis.
Because sperm production takes time, the effects of illness may not appear immediately on a semen analysis.
Motility and other sperm parameters may temporarily decline following significant illness.
If an abnormal semen analysis follows a recent high fever, repeat testing may be appropriate once sufficient time has passed.
Can Smoking Affect Sperm Motility?
Smoking has been associated with poorer semen quality.
Potential effects include changes in:
Sperm concentration
Motility
Morphology
DNA integrity
Stopping smoking can therefore be an important part of improving overall reproductive health.
Can Alcohol Affect Sperm Motility?
Excessive alcohol consumption can negatively affect male reproductive health.
Heavy alcohol use may influence:
Testosterone production
Hormonal balance
Sperm production
Semen quality
Reducing excessive alcohol intake can therefore be beneficial for men trying to optimise fertility.
Can Obesity Affect Sperm Motility?
Obesity is associated with several changes that may negatively affect male reproductive function.
These can include:
Hormonal alterations
Increased oxidative stress
Increased scrotal temperature
Metabolic dysfunction
Weight management may therefore form part of an overall approach to improving reproductive health.
Can Heat Affect Sperm Motility?
Sperm production is sensitive to temperature.
Repeated or prolonged exposure to significant heat may affect sperm development.
Possible sources include:
Hot tubs
Saunas
Certain occupational environments
Prolonged heat exposure
However, heat should be considered one possible contributing factor rather than automatically assumed to be the cause of poor motility.
Can Stress Affect Sperm Motility?
Stress can affect overall reproductive health through its effects on:
Hormonal function
Sleep
Sexual behaviour
Lifestyle
General wellbeing
However, a significantly abnormal semen analysis should not simply be attributed to stress.
Persistent low motility deserves proper medical evaluation.
Does Sperm Motility Change From One Test to Another?
Yes.
Semen parameters can vary between samples.
Differences may occur because of:
Abstinence duration
Recent illness
Fever
Medications
Lifestyle
Sample collection
Laboratory variation
For this reason, a single abnormal result may sometimes need confirmation.
How Is Low Sperm Motility Diagnosed?
The primary test is a semen analysis.
The laboratory evaluates sperm movement and classifies sperm according to their motility.
The specialist may also consider:
Sperm concentration
Total sperm number
Morphology
Semen volume
The combination of these results provides a much clearer picture than motility alone.
What Other Tests May Be Needed?
Additional testing depends on the severity and clinical context.
It may include:
Hormonal Tests
Testosterone
FSH
LH
Prolactin
Physical Examination
Assessment for:
Varicocele
Testicular abnormalities
Testicular volume
Reproductive tract abnormalities
Genetic Testing
May be considered when severe sperm-production abnormalities are present.
Imaging
Ultrasound or other investigations may be recommended when clinically indicated.
Can Low Sperm Motility Be Improved?
Sometimes.
The possibility of improvement depends on the underlying cause.
For example:
Varicocele→ Treatment may improve semen parameters in selected patients.
Hormonal disorder→ Appropriate hormonal treatment may restore sperm production.
Testosterone suppression→ Fertility-focused treatment may allow recovery of spermatogenesis.
Lifestyle factors→ Addressing smoking, obesity and other modifiable factors may support reproductive health.
But there is no single treatment that improves sperm motility in every man.
How Long Does It Take for Sperm Motility to Improve?
Improvement is not usually immediate.
Sperm production is a continuous biological process, and changes in the testicular environment can take time to appear in the semen.
The timeframe depends on:
Cause of the abnormality
Treatment used
Baseline sperm quality
Overall testicular function
Individual response
Follow-up semen analysis can help determine whether treatment is working .
Do Supplements Improve Sperm Motility?
A variety of supplements are marketed for male fertility, particularly antioxidants.
However, evidence for individual supplements varies.
They should not replace evaluation of an underlying condition such as:
Varicocele
Hormonal dysfunction
Genetic abnormalities
Testicular disease
Medication-related suppression
If motility is significantly abnormal, identifying the cause should remain the priority.
Can Low Motility Be Treated With IUI?
In selected cases, intrauterine insemination (IUI) may be considered.
During IUI, sperm are prepared in the laboratory and placed directly into the uterus.
This reduces the distance sperm need to travel through the reproductive tract.
However, IUI is not appropriate for every degree of male-factor infertility.
The total number of motile sperm available after processing is an important consideration.
When Is IVF or ICSI Considered?
If sperm motility is severely reduced, IVF with ICSI may be considered.
ICSI involves selecting an individual sperm and injecting it directly into an egg.
This can bypass several of the natural steps required for sperm to reach and fertilise the egg.
The decision depends on:
Sperm count
Motility
Morphology
Previous treatment
Female partner's fertility
Duration of infertility
Can a Man With Poor Motility Conceive Naturally?
Yes, depending on the severity.
A mildly reduced motility result does not necessarily prevent natural conception.
However, severely impaired motility may significantly reduce the probability.
The couple's overall fertility profile should be assessed before deciding whether to continue trying naturally or move to assisted reproduction.
Does Poor Motility Mean the Sperm Cannot Fertilise an Egg?
Not necessarily.
A semen analysis measures sperm movement under laboratory conditions.
It does not directly measure every aspect of sperm function or fertilisation ability.
Some sperm within a sample may still be capable of fertilisation even when overall motility is reduced.
This is one reason why semen analysis should be interpreted as part of a broader fertility assessment.
What If Almost All Sperm Are Immotile?
If nearly all sperm appear immotile, additional laboratory assessment may be required.
The specialist may need to determine whether the sperm are:
Alive but immotile
Non-viable
Affected by a rare sperm motility disorder
This distinction can be important when considering assisted reproduction.
In selected cases, viable immotile sperm may still be usable for ICSI.
What Is Total Motile Sperm Count?
The total motile sperm count (TMSC) combines sperm concentration, semen volume and the percentage of motile sperm.
It provides an estimate of the total number of moving sperm in the ejaculate.
TMSC can be useful when considering treatment options such as IUI.
However, it should still be interpreted alongside the rest of the semen analysis and the couple's clinical circumstances.
When Should Low Sperm Motility Be Investigated Further?
Further assessment is particularly important when:
Motility is severely reduced
The abnormality persists on repeat testing
Sperm count is also low
Morphology is abnormal
Azoospermia develops
There is a history of testicular disease
Testosterone or other hormones are abnormal
There is a suspected varicocele
Pregnancy has not occurred despite appropriate attempts
The more severe the abnormality, the more important it becomes to identify the underlying cause.
Low Sperm Motility vs Low Sperm Count
These are two different semen abnormalities.
Low Sperm Count
There are fewer sperm than expected.
Low Sperm Motility
A lower proportion of sperm are moving effectively.
A man can have one abnormality without the other.
He can also have both.
For example:
Low count + low motility + abnormal morphology
is sometimes referred to as oligoasthenoteratozoospermia (OAT).
When multiple parameters are abnormal, a more comprehensive evaluation is particularly important.
Sperm Motility and Male Fertility: Key Takeaway
Sperm motility is a major component of semen quality.
Healthy sperm need to move effectively to maximise the chance of reaching the egg.
Low motility can result from many factors, including varicocele, hormonal disorders, illness, lifestyle factors and testosterone suppression.
Importantly, low sperm motility is not necessarily permanent and does not automatically mean that natural conception is impossible.
The right approach is to identify the underlying cause, treat reversible factors where possible and consider assisted reproduction when appropriate.
Book a Male Fertility Consultation
If your semen analysis shows poor sperm motility, a specialist assessment can help determine whether there is an underlying hormonal, testicular, genetic or lifestyle-related cause.
Book a consultation with Professor Amr Raheem to discuss your sperm motility, semen analysis and fertility treatment options.
References
European Society for Sexual Medicine (ESSM). 16th ESSM Congress Joint with the 12th EFS Congress – Final Programme, Istanbul, 2014. The programme includes scientific material relating to male infertility and reproductive medicine. ESSM 2014 Scientific Programme
European Association of Urology (EAU). EAU Guidelines on Sexual and Reproductive Health – Male Infertility. Guidance on semen analysis, sperm parameters and evaluation of male infertility. EAU Male Infertility Guidelines
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