Everything You Need To Know About Sperm Motility When Trying To Conceive
Sperm motility refers to the ability of sperm to move or "swim." It is one of the factors tested in a semen analysis. Learn why it's important for fertility.
Medically reviewed by Matthew Wosnitzer, MD
Motility refers to the ability of an organism or fluid to move. By extension, sperm motility refers to the ability of sperm to move or "swim." Sperm motility is one component of sperm health that is tested in a sperm analysis.
Poor sperm motility (also known as asthenozoospermia) means that the sperm don't swim properly. Issues with motility are the leading cause of infertility in people with sperm. Read on to learn more about sperm motility, how it's measured, and how it impacts fertility.
Why Is Sperm Motility Important for Fertility?
Sperm are motile cells, which means that they make themselves move. This is important for fertility.
To conceive, a sperm cell must fertilize a mature egg. While an ovulated egg moves from the ovary into and through the fallopian tube thanks to the help of tiny hair-like projections called cilia, sperm must propel themselves.
With normal motility, sperm introduced into the vagina can make their way up the vaginal canal to the cervix, through the uterus, and eventually into the fallopian tube. The journey may take 10 minutes or so. Once there, the sperm must fertilize the egg, which also requires movement.
Related: 14 Things To Know If You're Having Sex To Get Pregnant
Sperm Motility and Semen Health
Motility is just one measurement of sperm and semen health. Other factors that are measured in a semen analysis include:
Semen volume: How much ejaculate there is, which is measured in milliliters (mL)
Total sperm count: How many sperm there are in the semen sample (average is 33 to 46 million sperm)
Sperm concentration: How many sperm are in 1 mL of ejaculate
Vitality: Percentage of live sperm
Sperm morphology: Shape of the sperm
Time to liquefaction: The time it takes for semen to naturally change from thick to liquidy (generally 20 to 30 minutes)
Semen pH: The acidity of the semen sample (semen that is too acidic can kill sperm)
White blood cell count: How many white blood cells are in the semen sample (a very high count can indicate infection)
Related: 12 Ways To Increase Male Fertility
Sperm Motility Measurements
If sperm motility is the only problem, the odds of spontaneous (unassisted) pregnancy are better than if other issues are present.
Motility Measurements in a Semen Analysis
Sperm motility may be evaluated in a semen analysis in the following ways:
Percentage motile: What percentage of all the sperm in a single ejaculate are moving
Percentage motile concentration: What percentage of sperm are moving in one measurement of semen, usually presented as millions of cells per mL
Total motile sperm count (TMSC): How many sperm are swimming in a single ejaculate (this number has been shown to be most relevant to male fertility prognosis)
Average path velocity (VAP): The speed sperm are moving, measured in microns per second (μm/s)
Healthy sperm motility isn't just about movement, but whether the movement is progressive and how many sperm are motile.
Progressive motility and non-progressive motility
How sperm move is also important for fertility. Progressive motility refers to sperm swimming in a mostly straight line or very large circles. Non-progressive motility refers to sperm that move but don't progress forward or swim in tight circles.
Total motility refers to the percentage of sperm making any sort of movement. This movement can include non-progressive movement. For example, a sperm that just vibrates in place would be considered motile but non-progressive. A sperm that zigzags but makes forward progression would be considered progressive. Progressive motility is needed for the sperm to swim their way up the reproductive tract and fertilize an egg.
Percentage of motile sperm
In a person with normal fertility, one ejaculate of semen may contain over 39 million sperm. Not all of those sperm are expected to be completely healthy.
For an ejaculate sample to be considered "normal," at least 40% of the sperm should be motile or moving, including non-progressive movement. At least 32% of the sperm should show progressive motility.
A diagnosis of poor sperm motility is usually made based on the percentage of motile sperm. However, research has found that the total motile sperm count is a more relevant measurement.
What's Considered "Normal?"
A total motile sperm count over 20 million is considered normal. Lower than 5 million is poor sperm motility. Less than 1 million is severe poor sperm motility.
What Affects Sperm Motility?
The following may harm sperm motility:
Exposure to chemicals
Illness
Exposure to heat or cold on the scrotum/testicles
Lifestyle habits like smoking
Abnormalities of the reproductive tract, like a varicocele (scrotal vein enlargement)
Poor sperm motility may also occur if a person has infrequent sexual activity. In this case, if the first ejaculate collected showed poor motility, a second ejaculate collected soon after should be better.
Usually, when sperm motility is poor, there are other problems found with sperm health. For example, people with poor sperm motility may also have low sperm counts or poor sperm morphology (or sperm shape). Sperm that aren't formed properly can't swim properly.
Related: Everything To Know About Male Infertility
How To Improve Sperm Motility
Aside from treating any underlying medical conditions or genetic factors that influence sperm motility, you can also make some lifestyle changes to improve sperm motility.
Quit smoking and quit or limit drinking
A meta-analysis of more than 20 studies found that people who smoke consistently have lower sperm counts. Another study found that those who use drugs and drink alcohol also experienced decreased sperm counts.
While it is unclear if sperm motility will rebound if these lifestyle factors are changed, it certainly cannot hurt to try.
Exercise
There is also some evidence that consistent exercise can improve sperm motility. One study explored the benefits of a 16-week aerobic exercise program consisting of at least three 50-minute sessions per week. Some of the participants experienced increased sperm count and motility.
Eat a nutritious diet
Eating a nutritious diet when trying to conceive may also improve sperm motility. While the best approach is to eat an overall balanced diet of nutrient-rich foods, there is some evidence that certain foods may have more impact on sperm health than others.
For example, one study found that foods rich in antioxidants like beta-carotene, beta-cryptoxanthin, lutein, and vitamin C may contribute to a healthy sperm count. Keep in mind, though, that no specific food is the key to increasing sperm count. Instead, focusing on the diet as a whole is the best way to improve fertility.
Related: 7 Tips for Conceiving Sooner
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