Varicocele and Male Infertility: What the Research Shows

Varicocele & Male Infertility share a critical connection, as the condition is present in roughly 15% of the general male population and impacts 35–40% of men evaluated for conception difficulties[1][2]. This treatable vascular problem disrupts sperm production and quality, often remaining undiagnosed for years. Current research confirms that surgical repair and catheter-based embolization significantly improve fertility outcomes, even in complex cases. Below, vascular surgeon Dr. Saher Arour in Dubai explains the latest evidence on diagnosis and treatment.

What Is a Varicocele?: The Vascular Problem Behind the Fertility Issue

A varicocele is an abnormal enlargement of the pampiniform plexus, the network of veins that drains blood from the testicle toward the abdomen[2]. Under normal conditions, one-way valves in these veins keep blood flowing upward. When these valves fail, blood pools, venous pressure rises, and the veins gradually dilate.

Varicoceles are enlarged veins in the scrotum and are a common condition, affecting about 15 % of adult men [1]. They are present in roughly 35 % of men with primary infertility and up to 80 % of men with secondary infertility [2] . These enlarged veins usually occur on the left side because the left testicular vein enters the kidney vein at a sharp angle, increasing pressure [3]. Studies also show that up to half of men with a varicocele have dilated veins on both sides, while an isolated right-sided varicocele is rare [2].

In many men, a varicocele causes no symptoms, but prolonged warmth and pooling of blood can damage sperm and interfere with hormone production [2]

Varicocele and Male Infertility: Damages Sperm

The Heat Hypothesis

Healthy spermatogenesis requires a testicular temperature approximately 2–4°C below core body temperature[3]. The scrotum and pampiniform plexus work together as a heat-exchange system that maintains this narrow thermal range.

When a varicocele forms, dilated veins surround the testicle and impair this cooling mechanism. Venous blood stagnates in the scrotal veins, leading to sustained elevation of scrotal and testicular temperature above the level that spermatogenesis tolerates[3]. Even mild but persistent temperature increases have been associated with measurable impairments in sperm concentration, motility, and morphology.

Oxidative Stress and DNA Fragmentation

Varicocele also promotes oxidative stress inside the testicle. Elevated venous pressure and sluggish blood flow are associated with increased production of reactive oxygen species (ROS) and inflammatory mediators in testicular tissue[4]. When ROS levels exceed local antioxidant capacity, they damage cell membranes, mitochondria, and nuclear DNA in developing sperm.

Sperm DNA fragmentation index (DFI) is an important marker of sperm DNA damage. However, there is no unanimous consensus on a single DFI cut-off value, and a recent meta-analysis suggests that a cut-off of 20% can potentially differentiate between fertile and infertile men [4] While SCSA DNA fragmentation index (DFI) >30% is consistently associated with negative pregnancy outcome in natural conception and intrauterine insemination (IUI), the reported cut-off values in predicting ART outcome vary, and infertility may occur when SCSA DFI reaches 20–25% [5]. In men with clinically relevant varicocele, elevated sperm DNA fragmentation may accompany abnormal semen parameters, and varicocele is associated with oxidative stress, spermatogenesis abnormalities, and testosterone secretion abnormalities [6] For this reason, sperm DNA fragmentation testing may be considered in selected situations such as previous failed ART, before in-vitro fertilization, or when there is a history of recurrent pregnancy loss [7].

Hormonal Disruption

Varicocele can disturb Leydig cell function, the cells responsible for producing testosterone in the testicle. Chronic venous congestion, hypoxia, and oxidative stress may impair their ability to maintain normal hormone output[6]. In some men this translates into low or borderline-low serum testosterone levels, often combined with reduced sperm production.

Several clinical studies have shown that successful varicocele repair can lead to modest but clinically relevant increases in serum testosterone, particularly in men who had low baseline levels[7]. This dual impact on sperm production and hormonal balance helps explain why treating a significant varicocele may improve semen quality and some symptoms related to low testosterone in selected patients.

Varicocele Symptoms: Why Many Men Do Not Know They Have One

Common Symptoms

Some men with varicocele notice a dull, dragging ache or a sense of heaviness in one or both testicles, especially after prolonged standing or physical exertion. The discomfort is usually mild to moderate and may be relieved by lying down[8]. On examination, a typical finding is a soft, compressible mass in the scrotum, often described as feeling like a “bag of worms”. In more advanced cases, the veins can be visible under the scrotal skin when the patient is standing.

The Silent Majority

A large proportion of varicoceles cause no noticeable symptoms. These silent varicoceles are often discovered only when a couple undergoes a fertility assessment and the male partner receives a semen analysis and physical examination[5]. Clinically significant varicoceles can be associated with reduced testicular volume, abnormal semen parameters, and higher markers of oxidative stress even in men who feel well[5].

Grading Varicocele: Why Grade Matters for Treatment Decisions

The Clinical Grading System

Clinicians commonly use a three grade system, originally described by Dubin and Amelar, to classify varicoceles on physical examination[6]:

Grade 1: Small varicocele that is not palpable at rest but can be felt during a Valsalva manoeuvre.
Grade 2: Varicocele that is palpable without Valsalva but not visible through the scrotal skin.
Grade 3: Large varicocele that is clearly visible through the scrotal skin.

Higher grades are more likely to be associated with testicular volume loss and more marked impairment of semen parameters, although there is not a perfect one to one correlation in every individual[1]. Grade 3 varicoceles with abnormal semen results are often candidates for intervention in men seeking to preserve or improve fertility.

Subclinical Varicocele

A subclinical varicocele is not detectable on physical examination but appears on Doppler ultrasound as dilated veins with reflux. Whether subclinical varicoceles should be treated remains controversial[6]. Current reviews tend to prioritize treatment for clinically palpable varicoceles in men with documented infertility and abnormal semen parameters[1].

Diagnosis: How Varicocele Is Correctly Assessed

Physical Examination

The starting point for diagnosis is a careful physical examination by an experienced clinician. The patient is examined in the standing position, since gravity helps reveal venous dilation. Grade 2 and grade 3 varicoceles can usually be detected in this way, and a Valsalva manoeuvre may be used to accentuate smaller grade 1 lesions[8].

Scrotal Doppler Ultrasound: The Key Imaging Tool

Color Doppler ultrasound is the main imaging tool used to confirm and characterize varicoceles. It helps assess pampiniform plexus vein diameter and venous reflux during Valsalva. Current guideline-based criteria use multiple veins with a diameter >3 mm and reversal of blood flow during Valsalva, while the EAU recommends a diameter of 3 mm or greater in the upright position during Valsalva with venous reflux lasting more than 2 seconds. [7]

Ultrasound is especially helpful when physical examination is equivocal, when subclinical varicocele is suspected, or when planning treatment in recurrent or bilateral cases[6]. It also allows evaluation of testicular volume and exclusion of other scrotal pathologies.

Semen Analysis and DNA Fragmentation Test

A basic semen analysis remains a cornerstone of the male infertility work up. The laboratory assesses sperm concentration, total count, motility, and morphology, usually using World Health Organization reference standards[5]. Abnormalities such as oligospermia, asthenospermia, or teratozoospermia are common in men with clinically significant varicocele.

When there is a history of repeated IVF failure, unexplained recurrent miscarriage, or discordance between semen parameters and clinical suspicion, a sperm DNA fragmentation test can add important information. Many groups consider DFI values above about 25–30% as indicative of meaningful DNA damage with potential negative impact on natural and assisted conception[4][5].

Treatment Options: What the Evidence Says

Surgical Ligation: The Traditional Approach

Surgical ligation, or varicocelectomy, has been used for decades to treat varicocele. The goal is to interrupt the dilated veins draining the testicle so that blood is redirected through healthier collateral pathways. The procedure can be performed through open inguinal or subinguinal incisions, high retroperitoneal ligation, laparoscopic ligation, or microsurgical subinguinal varicocelectomy[8].

Recurrence rates vary significantly depending on technique. Older high ligation and some laparoscopic methods have reported recurrence rates approaching 10–15%, largely because small accessory veins may be missed[6]. Microsurgical subinguinal varicocelectomy, which uses magnification to identify and preserve arteries and lymphatics while ligating all relevant veins, generally achieves recurrence rates below 1–2% in experienced hands[8].

Catheter-Based Embolization: The Superior Option for Complex and Recurrent Cases

Catheter-based varicocele embolization is a minimally invasive endovascular technique that treats the affected spermatic vein from inside the vascular system. The vein is catheterised, selective venography is performed to define the anatomy, and the vessel is then embolised using coils, sclerosant agents, glue, or a combination of materials. Transcatheter embolisation is performed as a day-case procedure under intravenous sedation and analgesia. [8]

In most patients, embolization is performed through a tiny venous access point rather than a formal surgical incision, and it is usually done as a day-case procedure. Published studies show that varicocele embolization is a well-tolerated technique and, in selected infertile men with grade III varicocele and abnormal semen parameters, it is associated with significant improvement in sperm concentration, motility, vitality, and morphology. [8]; [9]

Embolization is particularly useful in selected complex situations, such as recurrent varicocele after previous repair, bilateral disease that may need full venous mapping, or cases where detailed venography may help identify persistent refluxing veins. Because venous anatomy can vary from one patient to another, treatment planning should be individualized and based on physical examination, ultrasound findings, fertility goals, and specialist review.[7]

For more information about male infertility management in the context of complex varicocele, you can visit the internal page on Male Infertility Treatment Caused by Complex Varicocele.

How Long Before Sperm Parameters Improve?

A full spermatogenic cycle takes about 74 days from the earliest germ cell stage to mature spermatozoa entering the ejaculate[6]. After varicocele repair, semen parameters need time to reflect the improved venous drainage, lower temperature, and reduced oxidative stress.

Most studies evaluate semen changes at three-month intervals. Three months after varicocelectomy may be the optimal time for semen parameters compared to six months or even longer. In men with severe oligospermia, the largest improvement in total motile sperm count is typically seen from 3–6 months postoperatively, with minimal improvement thereafter. Several studies also report improved testosterone levels after repair, particularly in men with lower baseline levels. [⁠10] ; [11]; [12]

When to See a Vascular Specialist: Not Just a Urologist

Urologists and andrologists play a central role in evaluating male infertility, but some varicocele scenarios may also benefit from review by an interventional radiology or vascular team. Situations where that discussion may be useful include recurrent varicocele after previous repair, bilateral disease, clinical varicocele with abnormal semen parameters, and selected cases where sperm DNA fragmentation is high after failed ART or where there is a history of recurrent pregnancy loss. It may also be worth discussing for men who prefer a day-case procedure performed under sedation rather than open surgery. [5], [7], [8]

FAQ Section

Can a varicocele cause permanent infertility if left untreated?

Not every varicocele will lead to infertility, but clinically significant, long standing varicoceles are associated with testicular atrophy, impaired semen parameters, and higher oxidative stress markers in many men[1][5]. In some cases, the damage may become difficult to reverse if intervention is delayed for many years.

Does treating a varicocele guarantee pregnancy?

Treating a varicocele does not guarantee pregnancy. In selected infertile men with palpable varicocele and abnormal semen parameters, varicocele repair can improve sperm concentration and motility and is associated with higher rates of natural conception and assisted reproduction success compared with no treatment[6][8].

Is varicocele embolization available for complex or recurrent cases in Dubai?

Varicocele embolization is a recognised treatment option for selected complex or recurrent cases and is usually performed by an interventional radiologist. Patients should confirm local availability directly with a licensed hospital or specialist center, as service availability depends on the facility and the treating team.[9]

What is the difference between varicocele embolization and microsurgical varicocelectomy?

Microsurgical subinguinal varicocelectomy is an open procedure performed through a small incision, usually as a day-case operation, with the goal of ligating abnormal veins while preserving arteries and lymphatics.

Varicocele embolization is performed through a catheter, after venography has defined the anatomy, and is usually done as a day-case procedure under intravenous sedation and analgesia. Both approaches are established treatment options, and the best choice depends on the patient’s anatomy, fertility goals, prior treatment history, and local expertise. [9], [7]

How soon after varicocele treatment can we try to conceive?

Most specialists recommend reassessing semen parameters about three months after varicocele repair, since this corresponds roughly to one full spermatogenic cycle[6]. In couples planning assisted reproduction, a follow up semen analysis at 3–6 months helps the fertility team decide on the most appropriate next step[5].