What Is a Varicocele? A Plain-Language Guide to the Enlarged Scrotal Veins That Can Affect Fertility
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
TL;DR
A varicocele is an enlargement of the veins inside the scrotum, the loose bag of skin that holds the testicles. It forms when blood pools in these veins instead of flowing out efficiently, and it most often appears on the left side, usually developing during puberty. Many people never notice any symptoms, but some varicoceles can cause aching pain, slow testicle growth, lower sperm production, or fertility problems. Diagnosis is usually simple and painless, often just a physical exam and sometimes an ultrasound. Treatment is not always needed, and when it is, short outpatient procedures — stitching or clipping the vein shut, or blocking it with coils — can redirect blood flow into healthy veins and may improve sperm health.
Quick Answer
What is it? An enlargement of the veins that carry oxygen-depleted blood away from the testicles, caused by pooling blood.
When does it appear? Usually during puberty, developing slowly over time, most often on the left side.
What does it feel like? Often nothing at all; sometimes a dull, aching pain when standing or late in the day, and possibly a soft "bag of worms" lump above the testicle.
Does it affect fertility? Not always — but about 10% to 20% of men diagnosed with one have trouble fathering a child, and roughly 40% of men with fertility problems have a varicocele.
Is treatment always needed? No. It is treated when there is chronic pain, delayed testicle development, or sperm problems, using outpatient procedures.
What the research says
Varicoceles are common, including in men with no fertility problem. A systematic review of the epidemiology of varicocele reports that one is identified in 15% of healthy men and in up to 35% of men with primary infertility, and notes that the epidemiology remains incompletely understood. (Alsaikhan et al., Asian J Androl, 2016)
Microsurgical repair had the best results in a review of surgical approaches. A systematic review of 112 studies (56 in the quantitative analysis) found that the highest fertility rates and lowest complication rates were associated with the microsurgical subinguinal approach. It reported that 26% to 40% of patients undergoing varicocelectomy achieve short-term spontaneous pregnancy, and that up to 90% of those operated on for pain improved or had resolution of symptoms. Mayo Clinic cautions that when surgery is done mainly for pain, the pain may worsen or change in nature, so the decision should be made with your doctor. (Lundy and Sabanegh, Arab J Urol, 2017)
What is a varicocele?
A varicocele (pronounced VAR-ih-koe-seel) is an enlargement of the veins within the loose bag of skin that holds the testicles, called the scrotum. These veins carry oxygen-depleted blood away from the testicles. A varicocele happens when that blood pools in the veins instead of circulating efficiently out of the scrotum.
Varicoceles usually form during puberty and develop gradually over time. They may cause some discomfort or pain, but they often produce no symptoms or complications at all.
What does a varicocele feel like?
A varicocele usually occurs on the left side of the scrotum and often produces no signs or symptoms at all. When it does cause signs, they tend to follow a recognizable pattern.
Sign or symptom | What it looks or feels like |
Pain | A dull, aching pain or discomfort, more likely when standing or late in the day. Lying down often relieves the pain. |
A mass in the scrotum | If large enough, a lump like a "bag of worms" may be visible above the testicle. A smaller varicocele may be too small to see but noticeable by touch. |
Differently sized testicles | The affected testicle may be noticeably smaller than the other. |
Infertility | It may lead to difficulty fathering a child, but not all varicoceles cause infertility. |
When should you see a doctor?
Annual wellness visits for boys are important for monitoring the development and health of the testicles, and it is worth scheduling and keeping these appointments.
A number of different conditions could contribute to pain, swelling, or a mass in the scrotum. If you experience any of these, see your healthcare provider to get a timely and accurate diagnosis.
What causes a varicocele?
The testicles receive oxygen-rich blood through two testicular arteries — one for each side of the scrotum. Two testicular veins then carry oxygen-depleted blood back toward the heart. Within each side of the scrotum, a network of small veins called the pampiniform plexus carries this blood from the testicle to the main testicular vein. A varicocele is simply the enlargement of this vein network.
The exact cause of a varicocele is unknown. Two explanations are thought to play a role:
Contributing factor | How it may lead to a varicocele |
Faulty vein valves | Malfunction of the valves inside the veins that are meant to keep blood moving in the right direction. |
The left vein's unique path | The left testicular vein follows a slightly different path than the right vein, making a blood-flow problem more likely on the left. |
When the oxygen-depleted blood backs up in the network of veins, the veins widen (dilate), creating the varicocele.
Are there any risk factors?
There do not appear to be any significant risk factors for developing a varicocele. It is simply not well understood why it happens in one person and not another.
What problems can a varicocele cause?
Having a varicocele can make it difficult for the body to regulate the temperature of the testicles. Oxidative stress and the buildup of toxins can result, and these factors may contribute to complications.
Complication | What happens |
Poor testicular health | For boys going through puberty, a varicocele may inhibit testicle growth, hormone production, and other factors related to the health and function of the testicle. For men, it may result in gradual shrinkage due to tissue loss. |
Infertility | A varicocele does not necessarily cause infertility. An estimated 10% to 20% of men diagnosed with a varicocele experience difficulty fathering a child. Among men with fertility problems, about 40% have a varicocele. |
How is a varicocele diagnosed?
A healthcare provider can usually diagnose a varicocele with a simple physical exam — visual inspection of the scrotum and touch. You will likely be examined while lying down and while standing up.
While standing, your provider may ask you to take a deep breath, hold it, and bear down, similar to the pressure used during a bowel movement. This technique, called the Valsalva maneuver, can make a varicocele easier to examine.
Your provider may also order an ultrasound exam. Ultrasound uses high-frequency sound waves to create images of structures inside your body. These images may be used to confirm the diagnosis or characterize the varicocele, rule out another condition as a possible cause of the signs or symptoms, or detect a lesion or other factor obstructing blood flow.
Does a varicocele always need treatment?
No — a varicocele often does not need to be treated at all. The decision depends on who you are and what it is doing.
Situation | Typical approach |
No pain, no complications | No treatment needed. |
Teenager or young adult not seeking fertility treatment | Annual checkups to monitor any changes; surgery may be recommended if a testicle shows delayed development, there is a low sperm count or other sperm irregularities, or there is chronic pain not managed by pain medication. |
Man experiencing infertility | Surgery to correct the varicocele may be part of the fertility treatment plan. |
Note that sperm testing is usually only done in adults, not teenagers.
What are the treatment options?
The purpose of surgery is to seal off the affected vein to redirect blood flow into healthy veins. This is possible because two other artery-and-vein systems also supply blood circulation to and from the scrotum.
Varicocele surgery
Treatment outcomes may include the following:
The affected testicle eventually may return to its expected size. In the case of a teenager, the testicle may "catch up" in development.
Sperm counts may improve, and sperm irregularities may be corrected.
Surgery may improve fertility or improve semen quality for in vitro fertilization.
Varicocele repair presents relatively few risks, which might include a buildup of fluid around the testicles (hydrocele), recurrence of varicoceles, infection, damage to an artery, chronic testicular pain, or a collection of blood around the testicle (hematoma). The balance between benefits and risks shifts if the treatment is only for pain management: most varicoceles do not cause pain, and when surgery is done primarily to treat pain, there is a risk that the pain may worsen or change in nature.
Procedure | How it works | How long it takes |
Microscopic varicocelectomy | The surgeon makes a tiny incision low in the groin. Using a powerful microscope, the surgeon identifies and ligates (stitches or clips shut) several small veins. | Usually 2 to 3 hours |
Laparoscopic varicocelectomy | The surgeon works through a few very small incisions in the lower abdomen using a video camera and surgical tools. Because the vein network is less complex above the groin, fewer veins need to be closed. | Usually 30 to 40 minutes |
Both procedures require general anesthesia and are outpatient procedures that usually allow you to go home the same day.
Recovery from surgery: Pain is generally mild but might continue for several days or weeks. Your doctor might prescribe pain medication for a limited period after surgery, then advise nonprescription pain medicine such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others). You will likely be able to return to work about a week after surgery and resume exercise about two weeks after surgery. Ask your surgeon when you can safely return to daily activities or have sex.
Embolization: an alternative to surgery
In this procedure, a vein is blocked by essentially creating a tiny dam. A doctor who specializes in imaging (a radiologist) inserts a tiny tube into a vein in your groin or neck. A local anesthetic is used at the insertion site, and you may be given a sedative to reduce discomfort and help you relax.
Using imaging on a monitor, the tube is guided to the treatment site in the groin. The radiologist releases coils or a solution that causes scarring, creating a blockage in the testicular veins. The procedure lasts about an hour.
Recovery time is short, with only mild pain. You will likely be able to return to work in 1 to 2 days and resume exercise after about a week. Ask your radiologist when you can resume all activities.
Can you ease discomfort at home?
If you have a varicocele that causes minor discomfort but does not affect your fertility, you might try the following for pain relief:
Take nonprescription pain medicine, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others).
Support the scrotum by wearing an athletic supporter or snug briefs.
What questions will your doctor ask?
A varicocele that causes no pain or discomfort — which is common — may be diagnosed during a routine wellness exam. It may also be discovered during a more complex diagnostic process for fertility treatment. If you are experiencing pain or discomfort in your scrotum or groin, be prepared to answer the following questions:
Question your doctor may ask | Why it matters |
How would you describe the pain? | Helps characterize whether it matches varicocele pain. |
Where are you experiencing it? | Confirms the location. |
When did it begin? | Helps track how the condition developed. |
Does anything relieve the pain? | Lying down often relieves varicocele pain. |
Is it constant, or does it come and go? | Varicocele pain often appears when standing or late in the day. |
Have you had any injury to your groin or genitals? | Rules out injury-related causes. |
What medications, dietary supplements, vitamins, or herbal remedies do you take? | Provides a complete health picture. |
The Bottom Line
A varicocele is a common enlargement of the scrotal veins that often appears around puberty and frequently causes no symptoms at all. When it does cause trouble — aching pain, slowed testicle development, lower sperm counts, or fertility problems — treatment is available. Diagnosis is quick and painless, relying on a physical exam and sometimes an ultrasound, and outpatient procedures can redirect blood flow, protect the testicle, and may improve sperm health with short recovery times. The most important step is simply staying current with regular wellness visits so that a varicocele, or anything else affecting the testicles, is caught early.
Take the Next Step
If you notice scrotal pain, swelling, a lump, or a testicle that looks or feels different in size, schedule an appointment. A simple exam can confirm what is happening and show you whether watchful waiting or an outpatient treatment is the right path.
Frequently Asked Questions
Is a varicocele the same as a varicose vein?
They are related but not the same. A varicocele is an enlargement of the veins inside the scrotum. Varicose veins are enlarged veins that most often affect the legs. Both involve blood pooling when vein flow is impaired.
Does a varicocele go away on its own?
Varicoceles usually form during puberty and develop over time. Many never cause symptoms or problems, and a varicocele often doesn't need to be treated at all.
Does every varicocele cause infertility?
No. An estimated 10% to 20% of men diagnosed with a varicocele experience difficulty fathering a child. Among men with fertility problems, about 40% have a varicocele, which is why the varicocele is looked for during a fertility workup.
Why do varicoceles happen mostly on the left side?
The left testicular vein follows a slightly different path than the right vein, a path that makes a problem with blood flow more likely on the left.
Is surgery always needed?
No. A varicocele often doesn't need to be treated. Surgery or embolization is considered when a testicle shows delayed development, there is a low sperm count or other sperm irregularities, or there is chronic pain not managed by pain medication.
How long does recovery take after varicocele treatment?
After surgery, most people return to work in about a week and resume exercise in about two weeks. After embolization, recovery is shorter: about 1 to 2 days back to work and about a week before resuming exercise.
What can I do at home for mild discomfort?
For minor discomfort that doesn't affect fertility, nonprescription pain medicine such as acetaminophen or ibuprofen and wearing an athletic supporter or snug briefs to support the scrotum may help.
Can lying down relieve varicocele pain?
Yes. The dull, aching discomfort of a varicocele is more likely when standing or late in the day, and lying down often relieves the pain.
Will the testicle regrow after treatment?
Treatment outcomes may include the affected testicle eventually returning to its expected size. In a teenager, the testicle may catch up in development, and sperm counts may improve.
Who should evaluate a painful lump in the scrotum?
Because a number of conditions could cause pain, swelling, or a mass in the scrotum, a healthcare provider should evaluate it to give a timely and accurate diagnosis.
Related Reading
References
Mayo Clinic Staff. Varicocele: Symptoms and causes. Mayo Clinic. Last updated October 25, 2024. Accessed October 14, 2026. https://www.mayoclinic.org/diseases-conditions/varicocele/symptoms-causes/syc-20378771
Mayo Clinic Staff. Varicocele: Diagnosis and treatment. Mayo Clinic. Last updated October 25, 2024. Accessed October 14, 2026. https://www.mayoclinic.org/diseases-conditions/varicocele/diagnosis-treatment/drc-20378772
Alsaikhan B, Alrabeeah K, Delouya G, et al. Epidemiology of varicocele. Asian J Androl. 2016;18(2):179-181. PMID: 26763551. https://doi.org/10.4103/1008-682X.172640
Lundy SD, Sabanegh ES. Varicocele management for infertility and pain: a systematic review. Arab J Urol. 2017;16(1):157-170. PMID: 29713547. https://doi.org/10.1016/j.aju.2017.11.003
Disclaimer: This guide is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any questions about a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read here.
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