Low Sperm Count (Oligospermia): Causes, Tests and Treatment Options
A low sperm count, or oligospermia, means fewer than 16 million sperm per millilitre of semen. It lowers the chance of natural pregnancy but rarely rules it out. Treatment depends on the cause, so a urologist looks for that first.
Medically reviewed by Assoc. Prof. Dr. Tuncay Taş, urologist. Updated November 2026.
This guide explains what the numbers on a semen report mean and which medical causes a urologist checks. It then shows how doctors treat each cause. Finally, it explains when IVF with ICSI makes more sense than waiting.
What counts as a low sperm count?
The World Health Organization sets reference values from men who fathered a child within a year. For sperm concentration, the lower value is 16 million per millilitre. For the whole sample, it is 39 million sperm.
However, these figures are not a strict pass or fail line. Some men below them father children naturally. Meanwhile, some men above them still have fertility problems, for example because of poor movement or DNA damage.
How doctors grade oligospermia
Grade | Sperm per millilitre | What it usually means |
Mild | 10 to 15 million | Natural pregnancy often still possible; check for a treatable cause |
Moderate | 5 to 10 million | Lower natural chance; cause-based treatment or assisted conception |
Severe | Below 5 million | Genetic and hormone tests advised; ICSI often needed |
Cryptozoospermia | Sperm found only after spinning the sample | Close to azoospermia; sperm freezing worth discussing |
Also, the count is only one part of the report. Movement, called motility, and shape, called morphology, matter too. When all three are low, doctors call it oligoasthenoteratozoospermia, or OAT for short.
Why one test is not enough
Sperm counts vary a lot from week to week. For example, a fever, a short abstinence time or an incomplete sample can lower one result. So the NHS advises a second semen analysis about three months after the first.
For the most accurate result, collect the sample after two to seven days without ejaculation. Then deliver it to the lab within an hour, kept at body temperature.
Medical causes a urologist looks for
In many men, a careful assessment finds a cause. Some causes are easy to treat, while others mainly guide the choice of fertility treatment. The main groups are below.
Varicocele
A varicocele is a group of swollen veins in the scrotum. It warms the testis and raises oxidative stress, so it can lower count, movement and DNA quality.
In fact, it is the most common correctable cause of a low count. Our article does a varicocele cause infertility? explains who benefits from repair.
Hormone problems
The pituitary gland in the brain sends two hormones, FSH and LH, to drive sperm production. If the gland makes too little, the testes slow down. Doctors call this hypogonadotropic hypogonadism, and it is one of the most treatable causes.
Besides, a high prolactin level or a thyroid problem can also lower the count. A blood test picks these up, so it belongs in every assessment.
Testosterone and anabolic steroids
Testosterone gels, injections and anabolic steroids switch off the brain's signal to the testes. Consequently, sperm production falls, sometimes to zero. Many men do not know this, especially if a clinic prescribed testosterone for low energy.
Recovery after stopping is possible but slow. It can take many months, and sometimes the testes need hormone treatment to restart. So do not stop a prescribed medicine on your own; plan it with your urologist.
Testis problems from earlier in life
Undescended testes in childhood, even after surgery.
Mumps after puberty that caused painful swelling of the testis.
Testicular injury or torsion that reduced blood supply.
Cancer treatment with chemotherapy or radiotherapy.
Genetic causes
Genetic causes become more likely as the count falls. For example, mosaic Klinefelter syndrome or a small Y chromosome deletion can limit production. For this reason, doctors usually offer genetic tests when the count is below 5 million per millilitre.
The results matter for the whole family. Specifically, a Y chromosome deletion passes to any son conceived with ICSI. A genetic counsellor can explain what this means before treatment.
Partial blockages and ejaculation problems
Sometimes the testes make enough sperm, but fewer reach the semen. For instance, a partial blockage near the prostate lowers semen volume and count together.
Similarly, in retrograde ejaculation some semen flows back into the bladder. A urine test after ejaculation shows this.
Infection and inflammation
Infections of the epididymis or prostate can lower sperm quality and sometimes scar the ducts. A semen culture or urine test finds them, and antibiotics treat the active infection. However, scarring that has already formed may need surgery or sperm retrieval.
Tests for low sperm count
The tests aim to find the cause, not just confirm the number. Typically, your urologist combines a history, an examination and the tests below.
Test | What it checks | When it is used |
Two semen analyses | Count, movement, shape, volume | Every man; second test about three months later |
Hormone blood tests | FSH, LH, testosterone, prolactin, thyroid | Count below normal, or signs of hormone change |
Scrotal ultrasound | Varicocele, testis size, lumps | Most men with an abnormal result |
Genetic tests | Chromosomes and Y chromosome deletions | Count below 5 million per millilitre |
Post-ejaculate urine | Sperm in the bladder | Low semen volume |
Sperm DNA fragmentation | Breaks in sperm DNA | Repeated miscarriage or failed IVF |
How to read your hormone results
A low FSH and LH with low testosterone points to the pituitary gland. That pattern often responds to hormone treatment. By contrast, a high FSH suggests the testes themselves struggle, so hormone treatment helps less.
Normal hormones with a low count often point to a varicocele, a partial blockage or a lifestyle factor. In that case, the scan and the semen volume guide the next step.
Treatment options by cause
The best treatment fixes the cause where possible. Then, if pregnancy still does not follow, assisted conception uses the sperm that is present. The table matches common causes with their usual treatment.
Cause | Usual treatment | Time to see a change |
Palpable varicocele | Microsurgical varicocele repair | Three to six months |
Low pituitary hormones | Hormone treatment that replaces FSH and LH signals | Often six to twelve months or more |
Testosterone or steroid use | Planned stop, sometimes with hormone support | Several months to over a year |
High prolactin or thyroid problem | Treatment of the underlying gland problem | A few months |
Partial blockage | Surgery to open the duct, or sperm retrieval | Varies |
Genetic or unexplained cause | IVF with ICSI, sometimes after sperm freezing | Next IVF cycle |
Surgery
Microsurgical varicocele repair is the main operation for a low count. Assoc. Prof. Taş performs it through a small groin cut under an operating microscope. This keeps recurrence low.
The microscopic varicocelectomy page describes the steps and recovery.
Hormone treatment
Hormone treatment works best when the pituitary gland is the problem. It replaces or boosts the signals that tell the testes to make sperm.
Your urologist chooses the medicine and dose after the blood tests. So never start a hormone product on your own. Meanwhile, repeat semen tests track the response.
Assisted conception
IUI: prepared sperm placed in the womb; suits a mildly low count.
IVF: eggs and sperm meet in the lab; suits a moderate count.
ICSI: one sperm injected into each egg; suits a severe count or poor movement.
Donor sperm: an option the NHS lists when the count is very low and other routes fail.
Planning IVF abroad? Then read about IVF with ICSI in Turkey, which covers very low counts too.
What if the count drops to zero?
Some men with a severe low count later show no sperm at all. In that case, the diagnosis changes to azoospermia. Our guide to obstructive vs non-obstructive azoospermia explains the next tests and the sperm retrieval options.
For this reason, men with cryptozoospermia or a falling count often freeze sperm early. A frozen sample protects the option of ICSI if production drops further.
Lifestyle still matters, but it is rarely the whole answer
The NHS lists simple steps, such as less alcohol, no smoking, a healthy weight and loose underwear. These steps support sperm health.
However, they rarely fix a moderate or severe low count alone. So they should not delay a urological assessment.
How Assoc. Prof. Taş approaches a low sperm count
Assoc. Prof. Dr. Tuncay Taş starts with the cause rather than the number. First, he reviews both semen reports, the hormone results and any past medicines. Next, he examines the scrotum standing and lying down and adds an ultrasound.
Then he explains which causes are treatable and how long each treatment needs. If the female partner's age makes waiting risky, he plans the male treatment around the IVF timetable. The male infertility treatment page lists the full assessment.
When to see a urologist
See a urologist, not only a fertility clinic, if a semen test shows a low count. A urological assessment can find a treatable cause and, rarely, a serious condition such as a testicular tumour. In addition, arrange an assessment in these situations.
You have tried to conceive for 12 months, or 6 months if your partner is 36 or older.
A semen test showed fewer than 16 million sperm per millilitre.
You use or have used testosterone or anabolic steroids.
You notice a lump, swelling or ache in the scrotum.
You had undescended testes, mumps after puberty or cancer treatment.
To plan an assessment in person, book a consultation with Assoc. Prof. Taş or message the team on WhatsApp. Patients from the US, Canada and the UK receive a personal plan after the consultation. Then the coordinator arranges the days in Istanbul.
Frequently asked questions
What is considered a low sperm count?
The World Health Organization uses 16 million sperm per millilitre as the lower reference value. Below that, doctors call it oligospermia. Still, one result is not enough, so a second test usually follows about three months later.
Can you get pregnant with a low sperm count?
Yes, often. Many couples with a mildly low count conceive naturally, especially with sex every two to three days. However, the chance falls as the count drops, so a urologist and a fertility clinic should check both partners.
What is the most common treatable cause of low sperm count?
A varicocele, a group of swollen veins in the scrotum, is the most common correctable cause. Other treatable causes include hormone problems, past testosterone or steroid use, infections and partial blockages.
Can a low sperm count be cured?
It depends on the cause. A varicocele, a hormone problem or testosterone use can often be reversed. Genetic causes cannot, but IVF with ICSI can still use the sperm that is present.
Does testosterone therapy help a low sperm count?
No. Testosterone from outside the body tells the brain to stop the hormones that drive sperm production. As a result, it often lowers the count further. Men trying for a baby should discuss this with a urologist before starting or stopping it.
How long does it take to improve sperm count?
Sperm take about three months to form. So any change from treatment shows on a semen test about three months later, and often more fully after six months.
When is IVF with ICSI the better option?
ICSI suits severe oligospermia, a cause that cannot be treated, or a female partner whose age leaves little time. The embryologist injects one sperm into each egg, so even a very low count can be enough.
Sources
About the reviewer
Assoc. Prof. Dr. Tuncay Taş is a urologist in Istanbul with more than 20 years of experience and patients from over 60 countries. He graduated from Istanbul University in 2004, trained at Taksim Training and Research Hospital, completed a uro-oncology and laparoscopy fellowship at Heidelberg University and belongs to the EAU and the Endourological Society. Read his full profile.
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