A varicocele is a group of enlarged veins around a testicle, usually on the left side. It can cause aching, swelling or reduced testicular function, but many men have no symptoms. Treatment is not needed for every varicocele. For fertility, current NICE guidance says repair can be considered when it is clinically detected and semen parameters are reduced.

What is a varicocele?

A varicocele develops when veins in the spermatic cord become enlarged and blood does not drain normally from around the testicle. It is often compared with varicose veins in the leg.

Varicoceles are more common on the left because the veins on each side follow different anatomical routes. They may become noticeable during puberty or be found later during an examination for pain, swelling or fertility problems.

A varicocele is not cancer. However, a new scrotal lump should not be self-diagnosed. A clinician needs to distinguish enlarged veins from other causes of swelling, including conditions that require urgent treatment.

What does a varicocele feel like?

Many varicoceles cause no symptoms. When symptoms occur, they can include:

• A soft swelling above or around the testicle, sometimes described as feeling like a “bag of worms”
• A dull ache or dragging sensation
• Discomfort that becomes worse after standing, exercise or later in the day
• A difference in testicular size
• A swelling that becomes more noticeable when standing or straining
• Fertility problems found through semen testing

Seek urgent medical help for sudden severe testicular pain, especially with nausea or a testicle that appears higher than usual. Testicular torsion is an emergency and should not be mistaken for ordinary varicocele discomfort.

Ask a GP to assess a hard lump in a testicle, rapid swelling, a new right-sided varicocele, a swelling that does not reduce when lying down or any unexplained change.

Can a varicocele cause male infertility?

A varicocele can be associated with reduced semen quality and impaired testicular function, but the relationship is not simple. Many men with a varicocele conceive without treatment, and not every abnormal semen result is caused by the varicocele.

Possible mechanisms include higher temperature around the testicle, altered blood flow, oxidative stress and changes in the testicular environment. These may affect sperm concentration, movement or shape in some men.

The presence of a varicocele does not establish that it is the only or main fertility problem. A proper assessment should also consider:

• At least one diagnostic semen analysis, repeated if abnormal
• Medical, surgical and reproductive history
• Medication, testosterone and anabolic-steroid use
• Hormone tests when indicated
• Testicular size and physical examination
• The fertility and age-related factors of the other partner

Read Semen Analysis Results Explained before interpreting an individual result.

Can a varicocele affect testosterone?

The testicles produce both sperm and testosterone, and a varicocele can be associated with altered testicular function. Some studies report changes in testosterone after repair, but this does not mean treatment is appropriate for everyone with low testosterone or that it will reliably correct symptoms.

Low testosterone requires a wider assessment. Symptoms, morning blood tests, repeat measurements and the hormones that control testicular function may all matter. If you want to conceive, tell the clinician before starting testosterone treatment because testosterone taken from outside the body can suppress sperm production.

How is a varicocele diagnosed?

Diagnosis normally begins with a clinical examination. A GP, urologist or andrologist may examine the scrotum while you are standing and lying down and ask you to bear down or cough. This can make enlarged veins easier to feel.

Clinicians may describe a varicocele by grade, based on whether it is visible or can be felt at rest or only during straining. The grading system should be explained rather than treated as a fertility prediction.

Ultrasound can assess the veins, blood flow and testicles when the examination is uncertain, anatomy needs clarification or another condition must be excluded. A varicocele seen only on an ultrasound is sometimes called subclinical. An imaging finding alone does not automatically justify fertility treatment.

When should a varicocele be treated for fertility?

The 2026 NICE fertility guideline recommends considering radiological or surgical treatment when all of the following apply:

• The varicocele has been detected on clinical examination
• The man is trying to conceive spontaneously
• Semen parameters are reduced

NICE says fertility factors affecting the female partner should also be taken into account. This is important because waiting for semen quality to change after repair may not be the best use of time in every couple.

Treatment may also be considered for persistent pain or testicular development concerns, but the decision and evidence may differ from fertility treatment.

Repair is generally less persuasive when:

• The varicocele is seen only on ultrasound and cannot be felt
• Semen parameters are normal
• There is no pain, testicular effect or fertility concern
• Another cause fully explains the fertility problem
• The likely delay or benefit does not fit the couple’s wider treatment plan

Ask the specialist to explain what outcome they expect in your particular circumstances: less pain, improved semen measurements, a better chance of spontaneous conception or support for another fertility treatment.

What are the treatment options?

Varicocele treatment blocks or ties off abnormal veins so blood drains through other vessels. The two main approaches are surgical repair and radiological embolisation.

Surgical varicocele repair

Varicocelectomy is an operation to divide or seal the enlarged veins. Techniques can include microsurgical repair through a small groin incision, open surgery or laparoscopic surgery. The available method and anaesthetic depend on the service and your anatomy.

Possible complications include bruising, infection, pain, fluid collecting around the testicle, injury to nearby structures, recurrence and failure to improve symptoms or fertility. Ask about the surgeon’s preferred technique and why it is suitable for you.

Varicocele embolisation

Embolisation is performed by an interventional radiologist. A small catheter is guided through a vein using X-rays, and coils or another blocking material are used to close the abnormal vein. It is commonly performed as a day-case procedure without a scrotal incision.

Possible complications include bruising where the catheter enters, temporary loin or scrotal discomfort, infection, contrast reaction, failure to reach or block the vein, recurrence and, very rarely, movement of embolisation material.

Surgery versus embolisation

Neither option is automatically best for every patient.

Who performs it?

• Surgical repair: Urological surgeon
• Embolisation: Interventional radiologist

How is the vein treated?

• Surgical repair: Tied, clipped or sealed through an operation
• Embolisation: Blocked from inside using a catheter

Anaesthetic

• Surgical repair: Depends on technique, often general or local with sedation
• Embolisation: Commonly local anaesthetic with or without sedation

Incision

• Surgical repair: Groin, abdominal or other small surgical incision
• Embolisation: Small catheter-entry site

Key limitations

• Surgical repair: Surgical and anaesthetic risks; recurrence is possible
• Embolisation: Anatomy may prevent access; uses X-ray and contrast; recurrence is possible

Availability, previous surgery, anatomy, pain, fertility goals, recovery needs and local expertise all influence the choice.

Will treatment improve sperm count or pregnancy chances?

Some men with a clinically detected varicocele and abnormal semen parameters improve after repair. The size and clinical importance of the change vary, and treatment cannot guarantee natural conception or remove every need for IVF or ICSI.

The 2026 NICE recommendation reflects evidence of higher pregnancy rates after surgical or radiological treatment in the subgroup with a clinical varicocele and abnormal semen analysis who are trying to conceive spontaneously.

Ask the specialist for an individual estimate based on:

• Your semen results and whether they were repeated
• Testicular examination and hormone results
• The varicocele grade and symptoms
• Both partners’ ages and fertility factors
• Time already trying to conceive
• Whether fertility treatment is already planned

How long after repair might semen results change?

Sperm production takes several weeks, so improvement is not assessed immediately. A clinician may repeat semen analysis around three months after treatment and again later if useful.

The appropriate schedule depends on the initial results and the couple’s timescale. Ask before the procedure when testing will occur, who will interpret it and what decision will follow if the result improves, stays the same or worsens.

Do not assume that post-treatment pain or swelling predicts the fertility outcome. Follow the procedure-specific recovery and urgent-contact instructions.

What should happen before deciding on treatment?

A good consultation should cover:

• Confirmation that the varicocele can be felt clinically
• At least one reliable semen analysis and confirmation of an abnormal result when appropriate
• Examination of both testicles
• Relevant hormone tests
• Other possible causes of the semen abnormality
• The other partner’s fertility assessment and timescale
• Observation, surgery, embolisation and assisted-conception alternatives
• Expected benefits, uncertainty, recovery and complications
• What happens if treatment does not improve the result

If the appointment focuses only on moving directly to IVF or ICSI, it is reasonable to ask whether a male-reproductive specialist should assess the varicocele and the wider cause of the abnormal semen result.

Questions to ask your urologist or fertility team

• Is the varicocele clinically detectable or seen only on ultrasound?
• Do my repeated semen results fit the group in whom NICE says treatment can be considered?
• Could another condition explain the result?
• What benefit are we aiming for: pain relief, semen improvement or spontaneous conception?
• How do surgery and embolisation compare for me?
• What are your recurrence and complication rates for the recommended procedure?
• How long will recovery take and when can I exercise or have sex?
• When will semen analysis be repeated?
• How does my partner’s fertility and our treatment timescale affect the decision?
• What is the plan if the procedure does not improve our chances?

The most important thing to remember

A varicocele is common and does not always need treatment. The fertility decision should be based on a clinical examination, reduced semen parameters and the circumstances of both partners. Ask what outcome repair is intended to improve and compare surgery, embolisation, observation and fertility treatment before deciding.

The original Male Fertility Hub session with Dr Steven Moser discusses diagnosis, sperm and hormonal effects, treatment and recovery. Any statement presented as his personal view should be checked against the recording and approved before publication.

You can also read Male Fertility Testing Through Your GP or join The Male Fertility Hub community.

Sources

• NICE guideline NG257: Management of male-factor fertility problems
  https://www.nice.org.uk/guidance/ng257/chapter/Management-of-male-factor-fertility-problems
• NICE guideline NG257: Rationale and impact, including varicocele
  https://www.nice.org.uk/guidance/ng257/chapter/Rationale-and-impact
• NICE guideline NG257: Investigation of fertility problems
  https://www.nice.org.uk/guidance/ng257/chapter/Investigation-of-fertility-problems-and-management-strategies
• University College London Hospitals: Varicocele embolisation
  https://www.uclh.nhs.uk/patients-and-visitors/patient-information-pages/varocele-embolisation
• Cambridge University Hospitals: Varicocele embolisation
  https://www.cuh.nhs.uk/patient-information/having-a-varicocele-embolisation/
• European Association of Urology: Male infertility guideline
  https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility

This article provides general information and does not replace an examination or individual advice from a urologist, andrologist or fertility specialist.