Low Sperm Count (Oligozoospermia)

• What is a low sperm count?
• What are the symptoms of low sperm count?
• What causes low sperm count?
• Types and severity of low sperm count
• When to see a doctor or fertility specialist

A low sperm count means there are fewer than 15 million sperm cells per millilitre of semen. Sperm count refers to the number of sperm cells in each mL of semen and is a key indicator of sperm quality and health.

Most men with a low sperm count experience no symptoms and only find out if they struggle to conceive and provide a sample for sperm analysis. However, there are some indirect signs to look out for. These include:

• Difficulties conceiving – an inability to conceive despite having regular unprotected sex.
• Erectile dysfunction – problems getting or maintaining an erection.
• Low sex drive – reduced libido or sexual desire.
• Testicular issues – discomfort, swelling or changes in how the testes feel.
• Hormonal indicators – reduction in body or facial hair.

Are there any visible signs of low sperm count?

No, you cannot tell if you have a low sperm count by appearance alone. Changes in semen colour or consistency might suggest issues that need diagnosing by a healthcare professional, but are not a definitive indication that you have a low sperm count. The only way you can know for certain whether you have a low sperm count is through sperm analysis. 

When might you suspect you have a low sperm count?

You might suspect you have a low sperm count if you are struggling to conceive despite having regular unprotected sex for a sustained period. If you and your partner are under 35 years of age, you should see a healthcare professional after 12 months of trying to conceive. If you and your partner are over 35, you should see a healthcare professional after six months of trying to conceive.  

You may also want to seek professional medical advice if you experience any of the indirect symptoms associated with a low sperm count, such as:

• Difficulties conceiving
• Erectile dysfunction 
• Low sex drive
• Testicular issues
• Hormonal indicators.

Low sperm count can be caused by medical, lifestyle and environmental factors. Medical causes include infections, hormone imbalances, genetic conditions and blockages in the male reproductive tubes. Lifestyle and environmental factors include diet, alcohol consumption, smoking and exposure to stress, pollutants and heat.

Medical causes

The medical causes of a low sperm count include:

• Varicocele – a medical condition where swollen veins in the scrotum heat up the testicles and impair sperm production.
• Infections – infections like chlamydia, gonorrhoea and prostatitis can damage testicular tissue and impact sperm production. 
• Hormone imbalances – issues with the pituitary gland or hypothalamus may lead to low testosterone levels, reducing the amount of sperm produced.
• Genetic conditions – conditions like Klinefelter syndrome and cystic fibrosis can cause abnormal sperm production.

Structural causes (blockages)

A low sperm count can also be caused by obstructions in the reproductive tubes that store and transport sperm. Blockages impede sperm cells and prevent them from combining with the semen, reducing sperm count. They tend to happen in three main areas:

• Epididymis – responsible for storing and transporting sperm.
• Vas deferens – propels sperm during ejaculation via muscle contractions.
• Ejaculatory duct – combines sperm with seminal fluid.

Obstructions can be caused by inflammation, scarring or infection and are often treatable.

Lifestyle and environmental factors

Lifestyle and environmental factors can cause issues with sperm production and reduce sperm count. Key lifestyle factors include:

• Smoking can cause oxidative stress to sperm producing cells and reduces sperm count. 
• Alcohol consumption can impact testosterone levels and affect sperm production, negatively.
• Excess body fat can lower testosterone levels and increase testicle temperature which reduces sperm count.
• High stress levels can trigger the release of cortisol, which suppresses testosterone and sperm production.
• Heat exposure can reduce sperm production because the testes function best at about 33°C to 35°C.
• Toxins exposure such as pesticides and heavy metals can disrupt hormones, cause oxidative stress and damage testicular cells, reducing sperm count.

Sperm count is measured on a sliding scale, and oligozoospermia can be mild, moderate or severe. The severity of oligozoospermia has important implications for male fertility. For instance, though 14.5 million sperm cells per mL is considered a low sperm count, the chances of conceiving via sexual intercourse are similar to someone with a “healthy” sperm count of 15 million sperm per mL. The more severe the oligozoospermia, the more difficult it will be to conceive via sexual intercourse.

What is azoospermia (no sperm count)?

Azoospermia is the complete absence of sperm in semen. It is sometimes referred to as having a zero sperm count. Around 1% of all men and 10% of men facing fertility challenges have azoospermia. It is considered a different condition from oligozoospermia, with distinct causes and treatments. Much like oligozoospermia, men with azoospermia often experience no notable symptoms. 

Low sperm motility and abnormal sperm

Sperm count is not the only factor in male fertility and sperm quality. Men can have a healthy sperm count but still struggle to conceive because of low sperm motility, abnormal sperm morphology or a large number of dead sperm cells.

Low sperm motility 

Sperm need to move in a relatively straight line at more than 25 micrometres per second to have a good chance of reaching and fertilising an egg. Sperm that meet these conditions are progressively motile. In healthy semen, at least 32% of sperm cells are progressively motile.

Poor sperm morphology

Sperm with split or curled tails, misshapen or twin heads or deformed midpieces are less likely to reach and fertilise an egg. Abnormal morphology can result in fertility challenges. All semen contains a large number of morphologically defective sperm, and you only need 4% of all sperm to be shaped “normally” for your semen to be considered healthy. 

Dead sperm cells

A large number of dead sperm in your semen is known as necrozoospermia and can significantly reduce your chances of conceiving via sexual intercourse. It is a relatively rare condition, and many cases can be treated.

If you are struggling to conceive, it is important to understand what is causing your fertility challenges so you can seek appropriate treatment. Semen analysis identifies the primary issue(s) and is a sensible and effective next step for any man concerned about their fertility.

Yes, you can still conceive via sexual intercourse with a low sperm count, but it depends on the severity of your oligozoospermia. In mild cases of oligozoospermia, conceiving can take longer than expected, and you may need to make lifestyle changes. In more severe cases, fertility treatment may be required to help you conceive. Even when conceiving via sexual intercourse is not possible, there are several options available to parents hoping to have a child.

Treatment for low sperm count depends on the cause and severity of the oligozoospermia. Increasing sperm count may include lifestyle changes and medical treatment. Depending on the results, you may need to consider fertility treatment as an option to achieve pregnancy.

You should seek help from a doctor or fertility specialist if:

• You and your partner are under 35 and have not conceived despite having regular unprotected sex for 12 months.
• You or your partner is over 35 and have not conceived despite having regular unprotected sex for six months.
• You have erectile dysfunction and struggle to get or maintain an erection.
• You are concerned about other medical conditions or treatments that may impact your fertility, e.g., you have contracted an STI or undergone cancer treatment.
• You have a chronic medical condition that may affect fertility, such as diabetes, heart disease or a genetic condition.
• You are concerned about your fertility.

If you are seeing a medical professional about your fertility for the first time, they will usually recommend semen analysis.

Can men run out of sperm?

Men cannot run out of sperm as the testes are always producing new sperm cells. However, age, lifestyle factors, medical and genetic conditions, and frequent masturbation can all reduce the number of sperm in semen.

How do I know if my sperm is healthy? 

Sperm analysis is the only way to know whether your sperm is healthy and meets all the parameters for sperm count, motility, morphology and semen volume. Some sperm abnormalities result in clear symptoms, but many have no notable symptoms and sperm analysis is essential.

Is “lazy sperm” the same as low sperm count? 

No, having “lazy sperm” is not the same as a low sperm count. “Lazy sperm” is a colloquial term for low sperm motility or asthenozoospermia. Low sperm motility is when fewer than 32% of sperm are progressively motile and the sample has a total motility count below 40%.

Can you tell if your sperm is healthy without a test?

You can tell whether your sperm are healthy by successfully conceiving or submitting a sample for semen analysis. If you are struggling to conceive, semen analysis is the quickest, most accurate and most effective way to assess semen quality.