Low Sperm Motility: Asthenozoospermia Causes and Treatments

Close-up of sperm cell displaying low sperm motility.

Sperm motility refers to the ability of sperm to move effectively. This is crucial in fertility as sperm must move efficiently through a woman’s reproductive system to fertilize her egg. Male infertility can result from poor sperm motility.

This article examines the effects of sperm motility on fertility. We also discuss the causes of low sperm motility and some steps you can take to improve it.

Sperm Health and Pregnancy

Globally, around 15-20% of couples are affected by infertility. 30-40% of those couples are infertile as a result of the man’s sperm quality, including low sperm motility. An additional 20% are infertile as a result of both male and female factors.(1)

In order to have a successful pregnancy, sperm health will play an important part. Some factors that are measured to determine sperm health and function include:

  • Motility How well and how fast the sperm swims.
  • Sperm Count The number of sperm cells present in a semen sample.
  • Morphology The shape of the sperm cells.
  • Capacitation – The sperm’s ability to reach and penetrate the egg

Male infertility is possible if there are problems involving one or more of these areas. A successful pregnancy also requires that sperm have the right number of chromosomes.

What is Low Sperm Motility?

Sperm motility refers to the movement of sperm. Motility can play a large role in fertility. There are two types of sperm motility, which refer to how individual sperm cells swim.

  • Progressive motility – when sperm move in a predominately straight line or large circles.
  • Non-progressive motility –  when sperm do not swim in a straight line, or swim in very small circles.

Normal sperm motility can be defined as sperm that moves forward at a minimum of 25 micrometers per second in order to reach and penetrate a woman’s egg. Low sperm motility (Asthenospermia or asthenozoospermia), is a condition where less than 32% of a man’s sperm moves efficiently.

There are several types of problems affecting sperm motility, including:

  • Slow or sluggish forward movement
  • Non-progressive motility (movement of less than 5 micrometers per second)
  • Lack of motility

Does Sperm Gender Affect Speed of Motion?

For a long time, many people have believed that sperm containing Y chromosomes (or “boy” sperm cells) swim faster than those with X chromosomes (“girl” sperm cells). Research has shown that this is not the case, and there is no observable difference in either speed or motility between X and Y sperm cells.(2)

Causes of Low Sperm Motility

Low sperm motility may be caused by a number of different factors. Some men might have a genetic condition, while others might have a medical condition that has not yet been diagnosed.

Certain environmental and lifestyle factors can also significantly affect sperm motility. For example, smoking has been shown to decrease sperm motility, especially when smoking 10 or more cigarettes daily.

Work-induced infertility can potentially be a problem for men whose occupations include working in the military, driving, painting, or repeated trauma to the pelvic area.

Another cause can be varicocele, which is a condition where the veins in the scrotum become enlarged. This condition has been associated with reduced sperm motility.

Low sperm motility could also be caused by a disorder involving the secretion of the male accessory sexual glands. The accessory glands of the male reproductive system include the seminal vesicles, the bulbourethral glands, and the prostate gland.

These glands secrete fluids that enter the urethra during ejaculation. Certain conditions can cause these glands to empty more slowly than normal.

Additionally, the quality of sperm can be affected by damage to the testicles which produce and store sperm. Testicular damage can be caused by a number of factors, including:

  • Injury
  • Infection
  • Testicular cancer
  • A genetic condition
  • Surgery involving the testicles
  • Undescended testes

Long-term anabolic steroid use use can also lead to a decrease in sperm count and motility. As well, semen quality can be affected by certain herbal supplements, and drugs like marijuana and cocaine.

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Testing For Sperm Motility

A routine semen analysis can measure sperm motility. You will need to submit at least two samples of your semen. These are normally provided by by masturbation at a medical office or testing lab.

You can also provide a sample of your sperm by either having sex with a specialized condom, or by by withdrawing during intercourse (coitus interruptus). Normal condoms should not be used for this purpose as they can contain spermicides or lubricants that could contaminate the sample.

The sample should remain at least at room temperature, and brought to the facility within 30-60 minutes. Doctors recommend that the sample be kept close to the body for transport to help keep it at body temperature. This will ensure the sample is of the highest quality possible when analyzed.

You are considered to have low sperm motility if less than 40% of your sperm is motile. Additionally, your doctor may also perform a semen analysis in order to test for other issues besides sperm motility, such as:

  • Health of the reproductive system
  • Accessory organs
  • Ejaculation
  • Treatments


Certain changes in lifestyle can potentially help to boost sperm motility in men.(3) These include:

Supplements For Sperm Motility

Certain supplements may boost sperm motility. For instance, one study showed that men who took 200 micrograms of selenium and 400 units of vitamin E daily for at least 100 days had a 52% increase of sperm motility.(4) Before you take supplements, consult with your doctor.

Also, be cautious about where you purchase sperm motility supplements. Nutritional supplements are not regulated, so they should only purchased from reputable sources.

See Also: The Best Supplements for Increasing Sperm Count


If low hormone levels or varicocele are the source of the poor sperm motility, then medications like follicle-stimulating hormone or human chorionic gonadotropin could help. Surgery could even be recommended by your doctor in some instances.


Male fertility can be affected by many factors. However, pregnancy can still occur with low sperm motility if the sperm is healthy otherwise.

Additionally, there are options available that are effective even when there are issues with sperm quality. For example:

  • IUI – Short for intrauterine insemination (also referred to as artificial insemination), IUI is a procedure that involves the collection and washing of sperm. The fastest-moving sperm can then be inserted into the womb through a fine plastic tube.
  • IVF – Short for “In vitro fertilization”, IVF is a procedure where a woman receives medication to increase the production of eggs, which are then taken from her ovaries and fertilized in a laboratory with sperm. The embryo is then placed into to the womb to continue normal development.
  • Sperm donor – An individual who wants to conceive might be able receive sperm from a donor to use in an IVF procedure.

The chances of conceiving can be greatly increased by using a reproductive technology like IUI or IVF. These methods work because using them does not require the sperm to swim on their own.


If you have not successfully been able to achieve a pregnancy after 12 months, talk to your doctor. By testing both you and your partner, your doctor can determine if either of you have
any fertility issues, and discuss what the next steps should be.

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  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4691969/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1440662/
  3. https://www.nhs.uk/common-health-questions/mens-health/how-can-i-improve-my-chances-of-becoming-a-dad/#infertility-in-men
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3048346/
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