Causes of Low Sperm Count in Nigerian Men

search for the causes of low sperm count and you get a list: smoking, heat, stress, weight, tight underwear. That list is not wrong, but it is close to useless, because it flattens together things that are trivially reversible with things that need surgery, and it gives you no way to work out which applies to you.

Doctors do not think about it that way. They organise the causes by where in the system the problem starts, because that is what determines the test to order and the treatment that will help. This article follows that framework.

What counts as a low sperm count

Under the WHO 2021 reference values, a low count means a concentration below 16 million sperm per millilitre or a total count below 39 million in the whole ejaculate. The clinical term is oligozoospermia. A complete absence of sperm is azoospermia, and sperm so few they appear only after centrifuging the sample is cryptozoospermia.

Those thresholds are the 5th centile of men whose partners conceived within a year, which means five per cent of proven-fertile men fall below them. A number under the line is a reason to investigate, not a diagnosis of infertility. You can check your own values with the semen parameter check.

How doctors group the causes

Sperm production runs along a chain: the brain signals the testes, the testes manufacture sperm, and a set of tubes carries them out. A problem anywhere along that chain lowers the count, but the three locations behave completely differently.

This matters practically. A post-testicular blockage means production is often perfectly normal and sperm can frequently be retrieved surgically. A pre-testicular hormonal problem may respond to medication. A testicular cause is usually the hardest to reverse, but varicocele, the commonest one, is also operable. Same low number on the report, three entirely different conversations.

1. Pre-testicular causes: the signal

Sperm production is driven by hormones. The hypothalamus and pituitary gland release FSH and LH, which instruct the testes to produce sperm and testosterone. If that signal is weak, production falls even though the testes themselves are healthy.

• Hormonal imbalance. Low FSH, LH or testosterone reduces sperm output. Thyroid and adrenal disorders can also interfere.
• Pituitary conditions, including tumours affecting the gland that produces these hormones.
• Anabolic steroid use. This deserves emphasis because it is common and widely misunderstood. Taking testosterone or steroids suppresses the body's own signalling and can sharply reduce sperm production. Men take them believing they boost virility; the effect on fertility is the opposite.
• Genetic and congenital conditions such as Kallmann syndrome, where the hormone needed to make sperm is not produced.
• Sexual dysfunction. Erectile dysfunction, premature ejaculation or anejaculation can prevent sperm being delivered even when production is normal.

Hormonal causes are worth identifying precisely because some respond to medication. This is why a hormone panel is a standard next step when a count is very low.

2. Testicular causes: the factory

These are problems inside the testes, where sperm are actually made. This group accounts for most identifiable cases.

Varicocele

An enlargement of the veins draining the testis, and the single most important entry on this list. It impairs production through several mechanisms at once: raised scrotal temperature, reduced oxygen supply, oxidative stress and disruption of the hormonal axis.

Varicocele is found in roughly 15% of men generally but in 35 to 40% of men with primary infertility. Critically, it is the most commonly surgically correctable cause of male infertility, and repair can improve count, motility and morphology. If you have a persistently low count and nobody has examined your scrotum, that is a gap.

Infection

Infections can damage the testes directly (orchitis), inflame the epididymis (epididymitis), or scar the ducts. Sexually transmitted infections including gonorrhoea and chlamydia are significant contributors, and childhood mumps affecting the testes can cause lasting damage. Most infections resolve without long-term consequence, but some do not, and untreated infection continues to do damage over time.

Heat

The testes sit outside the body because spermatogenesis needs to run several degrees below core temperature. Sustained heat impairs production and increases DNA damage. Hot baths and saunas, laptops on the lap, prolonged sitting, and occupational or climatic heat all contribute, and in hot climates this is a daily rather than occasional factor.

Other testicular causes

• Undescended testicles at birth, which raises the risk of reduced fertility in adulthood.
• Testicular injury, torsion or surgery, and removal of a testicle.
• Genetic conditions such as Klinefelter syndrome, where an extra X chromosome reduces sperm production.
• Cancer and its treatment. Radiation and chemotherapy can impair production, sometimes permanently, which is why sperm banking is discussed before treatment.
• Medications including some treatments for arthritis, depression, high blood pressure, digestive conditions and cancer, as well as testosterone replacement.

Same low number on the report, three entirely different conversations. That is why the location matters more than the list.

3. Post-testicular causes: the plumbing

Here sperm are made normally but cannot get out. This group is easy to miss and important to catch, because the outlook is often better than the report suggests.

• Obstruction. A blockage anywhere from within the testis to the ejaculatory duct. Causes include scarring from past infection, injury, surgical damage, and congenital absence of the vas deferens.
• Vasectomy, which cuts the vas deferens. Note that semen volume stays essentially unchanged, because the glands producing the fluid sit downstream of the cut.
• Retrograde ejaculation, where semen enters the bladder instead of leaving through the urethra. Diabetes, spinal injury, prostate or bladder surgery, and alpha-blocker medications can all cause it.

The reason this group is hopeful: obstructive azoospermia means production is intact. Sperm can often be retrieved directly from the testis or epididymis for use in assisted reproduction, and some blockages can be surgically reversed. Our article on the anatomy of sperm production shows the route and where obstructions occur.

Lifestyle and environmental factors

These usually act as contributors rather than sole causes, but they are the part you control.

• Smoking, which degrades every sperm parameter measured through oxidative stress.
• Heavy alcohol use, which lowers testosterone and reduces production.
• Excess weight, which converts testosterone to oestrogen and raises scrotal temperature. See our guide to BMI and male fertility.
• Recreational drugs, including cannabis and cocaine.
• Industrial and agricultural chemicals. Pesticides, insecticides, organic solvents and heavy metals such as lead are linked to lower sperm concentration, which matters for men in farming, painting and chemical industries.
• Radiation exposure, where recovery can take years and high doses may cause permanent reduction.
• Chronic stress, which has a real but modest and often overstated association.

One more item belongs here that is not a cause at all: testing artefacts. A sample taken too soon after the last ejaculation, collected incompletely, or produced shortly after a fever or illness can read falsely low. This is precisely why results are based on more than one sample.

What the Nigerian data shows

The global causes above all apply, but the regional pattern differs in one important respect.

In a prospective study of 504 consecutive Nigerian men investigated for infertility, varicocele was the commonest cause identified at 28.8%, with infection accounting for a further 20.8%. The authors specifically noted that the high incidence of infection was a major point of difference from Western studies. A case-control study of Nigerian men linked infertility to markers of sexually transmitted infection and to poor healthcare-seeking behaviour for those infections.

At population level, a systematic review across Sub-Saharan Africa put pooled infertility prevalence at roughly 17%, close to one couple in six, and identified sexually transmitted infections and pelvic inflammatory disease as significant risk factors with an odds ratio above three. A meta-analysis focused on Africa found male-related problems accounted for about 22% of cases outright with both partners affected in a further 21%, naming oligozoospermia, asthenozoospermia and varicocele as the commonest male causes. Reviews of Nigerian data put the male contribution at around 35 to 40% of cases.

Hospital series also show how much findings vary between centres: reported azoospermia rates range from under 9% in one tertiary population in Ogun State to far higher figures elsewhere, which reflects referral patterns rather than a single national picture. Separately, a ten-year observational study across Nigeria and South Africa reported declining semen parameters between 2010 and 2019, with progressive motility and morphology both falling as age increased.

The practical conclusion is consistent across all of it: the two leading identifiable causes in Nigerian series are both things medicine can act on, and both get worse the longer they are left.

Symptoms and when to see a doctor

The honest answer is that low sperm count usually has no symptoms at all. Most men feel completely well and function normally. The only sign is difficulty conceiving.

Where an underlying condition is present, there may be additional signs worth acting on:

• Pain, swelling or a lump in the testicle area
• Difficulty with erections, low libido, or problems with ejaculation
• Reduced facial or body hair, or breast tissue enlargement, suggesting a hormonal cause
• A history of undescended testicles, testicular injury, torsion, or groin surgery

See a doctor if you have been trying to conceive for twelve months without success, or six months if your partner is over 35. Go sooner, without waiting, if you have testicular pain or swelling, sexual function problems, or any history of the conditions above.

How it is diagnosed

Assessment is more straightforward and less invasive than most men expect.

1. 1History. Past illnesses and infections, surgeries, medications, occupation, and lifestyle.
2. 2Physical examination. Including examination of the scrotum for varicocele and signs of hormonal imbalance. This step finds treatable causes and is easily skipped.
3. 3Semen analysis. The central test, usually repeated because parameters fluctuate. Our guide to reading a report decodes every line.
4. 4Hormone panel. FSH, LH and testosterone, especially where the count is very low.
5. 5Scrotal ultrasound, to identify varicocele, obstruction or structural abnormality.
6. 6Genetic testing, where the count is extremely low or zero.

Treatment options

Treatment follows the cause, which is the whole reason the framework above matters.

• Treating infection. Antibiotics where an active infection is present. Prompt treatment prevents the scarring that causes lasting obstruction.
• Surgery. Varicocele repair is the most common, and can improve count, motility and morphology. Obstructions can sometimes be surgically corrected.
• Hormonal therapy, where a hormonal deficiency is identified.
• Stopping the cause. Discontinuing anabolic steroids or a contributing medication, under medical supervision.
• Lifestyle change. Weight, smoking, alcohol and heat, which support every other treatment
• Sperm retrieval and assisted reproduction. Where the count is very low or absent, sperm can often be retrieved directly and used in IVF or ICSI. These services are available in Lagos, Abuja, Port Harcourt and Ibadan among other cities, though cost is a real barrier. Our clinic directory lists providers by state and specialty.

Two honest points. First, in a substantial share of cases no cause is ever identified, which is frustrating but does not mean nothing can be done. Second, treatment timelines follow biology: because sperm take around 74 days to produce plus two weeks to mature, allow two to three months before re-testing.

What you can do

1. 1Get tested rather than waiting. A semen analysis is cheap, quick and non-invasive, and it is too often the last test done instead of the first.
2. 2Ask for a scrotal examination specifically. Varicocele is common, treatable, and invisible unless someone looks.
3. 3Treat infections promptly and mention any past urethral discharge or STI, even years later. Practise safer sex and get tested.
4. 4Keep cool. No very hot baths, no laptops on the lap, looser underwear, breaks from prolonged sitting.
5. 5Do not use anabolic steroids, and check with a doctor whether any medication you take affects sperm production.
6. 6Address weight, smoking and heavy drinking, the three lifestyle factors with the strongest evidence.
7. 7Use protection at work if you handle pesticides, solvents or heavy metals.

Fertility is a couple's issue, and testing both partners early is faster and cheaper than testing one and waiting. Male infertility is a medical condition, not a verdict on a man, and most men who get a low result have more options than they assume on the day they read the report.