Varicocele and fertility: what repair does and does not do.

A varicocele is a cluster of enlarged veins in the scrotum, like a varicose vein in the leg. About 15% of all men have one, rising to roughly 35 to 40% of men seen for infertility. Men with one tend to have lower sperm counts, and the gap widens with grade. Repairing a varicocele improves semen measurements on average and may raise the chance of pregnancy, but whether it raises live births is not established: the 2021 Cochrane review rated that evidence very low certainty. Guidelines agree on who repair is for: a varicocele a doctor can feel, semen results below the reference limits, and a couple trying to conceive without treatment. One found only on a scan, or found alongside normal semen, is not a reason for surgery.

What is a varicocele?

The veins that drain each testicle form a network called the pampiniform plexus. When the valves in those veins do not work well, blood pools and the veins widen. Men often describe the feel as a bag of worms, and larger ones can ache by the end of the day, though most cause no symptoms at all.

They are almost always on the left, and up to half of men with one have them on both sides [1]. Why the left is not settled. One venography study of 659 men with a left varicocele found no valves in the left spermatic vein in 484 of them [2], and the drainage route on the left is longer. A review describes the left-right drainage difference and incompetent valves as "the most quoted theories for varicocele development" [1], but neither is proven. A varicocele on the right alone is unusual. The EAU says it should prompt a closer look for an abdominal cause [3], although the AUA advises against routine abdominal imaging for an isolated small or moderate right varicocele [13].

How common are they?

• About 15% of men in general. In 7,035 young men from six European countries, 15.7% had a grade 1 to 3 varicocele [4].
• Around 25% of men with abnormal semen. The WHO task force study of 9,034 men across 24 countries found varicocele in 25.4% of men with abnormal semen against 11.7% of men with normal semen [5].
• 35 to 40% of men seen for infertility, on the EAU's figures [3]. In a series of 1,099 infertile men, 35% of those with primary infertility had one, rising to 81% of those who had fathered a child before and were now struggling [6].

That last figure gets quoted as proof that varicoceles do progressive damage. Treat it carefully: it comes from a single clinic, the men with secondary infertility were on average about four years older, and varicoceles become more common with age anyway, so age is a plausible alternative explanation [1].

How is one diagnosed and graded?

By examination, standing up, with and without bearing down. The grades the EAU uses are [3]:

• Subclinical: not felt or seen, only picked up on a scan.
• Grade 1: felt only when bearing down.
• Grade 2: felt at rest.
• Grade 3: seen and felt at rest.

Ultrasound is for when the examination is inconclusive, or when semen stays abnormal after a repair [3]. This matters more than it sounds: the method decides the answer. In one small study of 34 asymptomatic young men, 15% had a varicocele on examination and 35% had reflux on Doppler [7]. A scan finds things a hand does not, and those extra findings are the ones no guideline recommends treating.

What does a varicocele do to sperm?

The clearest mechanism is heat. Direct measurement found raised temperature inside the testis and on the scrotal skin in men with a varicocele, and scrotal skin temperature was raised on both sides even when the varicocele was on one [8]. Oxidative stress is the other commonly proposed mechanism, though the Cochrane reviewers note that "the mechanisms by which varicoceles affect fertility have yet to be satisfactorily explained" [9]. Reflux of blood and raised pressure are proposed rather than proven.

The association with semen quality is solid. In the 7,035-man European cohort, semen quality fell as grade rose, and men with a grade 3 varicocele had sperm concentrations less than half those of men without one [4]. FSH and LH were higher and inhibin B lower, which fits reduced testicular output. Testosterone was no different.

The association with actually having a baby is weaker. The WHO task force found that "spontaneous pregnancies were as frequent in couples in whom the men did or did not have varicocele" [5]. So a varicocele on its own, with normal semen, is not a finding that explains infertility.

Does repairing it help?

This is the question worth being careful about, because the honest answer splits in two.

Pregnancy: possibly, at low certainty. The 2021 Cochrane review pooled 48 randomized trials in 5,384 men. Against no treatment, repair gave a pregnancy risk ratio of 1.55 (95% CI 1.06 to 2.26) across 13 trials and 1,193 men, which the authors rated low certainty [9]. In plain terms, roughly 21 in 100 couples conceived without treatment, against something in the 22 to 48 range with it.

Live birth: not established. Only two trials and 204 men reported it, giving a risk ratio of 2.27 with a confidence interval from 0.19 to 26.93, rated very low certainty, with the two trials pointing in opposite directions. The review's own wording is that "we are uncertain whether surgical or radiological treatment improves live birth rates when compared to no treatment" [9]. NICE reached the same place, describing the live birth data as limited and mixed [10].

Semen measurements: yes, on average. A meta-analysis that included 17 studies found microsurgical repair was followed by about 9.7 million per mL more concentration (95% CI 7.3 to 12.1) and about 9.9 percentage points more motility (4.9 to 15.0) [11]. The gain tracks the grade: a review of 2,001 men found concentration rose by about 5.5 million per mL after repairing a grade 1 and about 16 million per mL after a grade 3 [12]. Bear in mind most of this pools before-and-after data rather than comparing against an untreated group, which flatters it.

So the fair summary is that repair, on average, moves the numbers on a report, may help a couple conceive, and has not been shown to produce more babies. Those are three different claims and they are often blurred into one.

What do the guidelines say?

They agree on the shape and differ on the force.

• NICE NG257 (March 2026) says to "consider radiological or surgical treatment (taking into account female fertility factors)" for people with a varicocele "detected on clinical examination" who "are trying to conceive spontaneously" and "have reduced semen parameters" [10]. NICE's committee was not aware of any randomized trial evidence on repairing a varicocele before IVF or ICSI, so it made no recommendation for that group [10].
• AUA and ASRM say clinicians "should consider surgical varicocelectomy in males attempting to conceive who have palpable varicocele(s), infertility, and abnormal semen parameters, except for azoospermic males", a moderate recommendation. They separately make a strong recommendation against repairing a varicocele "detected solely by imaging" [13].
• EAU is the most forward, with a strong recommendation to treat men who have a clinical varicocele, abnormal semen and otherwise unexplained infertility, where the female partner has good ovarian reserve. It pairs that with an equally strong recommendation not to treat men with normal semen or a subclinical varicocele [3].

Worth noticing: the EAU calls its recommendation strong, while the trials behind it are rated low certainty for pregnancy and very low certainty for live birth. Where guidelines diverge on the same data, that is usually a sign the data will not carry a confident answer either way.

Which repair method?

Microsurgical repair through a small groin incision comes out best on recurrence and hydrocele. The EAU's own figures put recurrence at 0.4% and hydrocele at 0.44% for the microsurgical approach, against 15 to 29% recurrence for open high ligation and 3 to 11% for radiological embolization [3]. Cochrane found microscopic subinguinal surgery had lower recurrence than other surgery (risk ratio 0.48, moderate certainty) and slightly higher pregnancy rates (risk ratio 1.18, moderate certainty), and was uncertain whether surgery or radiological treatment works better, on low-certainty evidence [9].

The practical catch, which NICE raises, is that microsurgery is likely to be preferred in specialist clinics but is not universally available [10]. Worth asking what a given unit offers.

Subclinical varicocele, testosterone and DNA fragmentation

• Subclinical. No guideline recommends repair. A review of 13 studies and 1,357 men found small changes in semen measurements that were not clinically meaningful and no increase in pregnancy [14].
• Testosterone. Repair is followed by a rise, but mostly in men who started low. One meta-analysis of 712 men found an average rise of about 34 ng/dL overall, around 123 ng/dL in men who were hypogonadal, and no significant change in men whose levels were normal [15]. It is not a reason to repair for fertility.
• Sperm DNA fragmentation. Repair lowers it by around 7 percentage points across 19 studies [16]. That said, NICE advises against testing DNA fragmentation at all [10], so for anyone following NICE this is not a number that enters the decision. The DNA fragmentation guide covers the test and where the guidelines differ.

How long until a change shows?

Sperm take about 74 days to develop [17], so nothing useful can be read from a sample taken a few weeks after surgery. In a study of 71 men, concentration, motility and total motile count were higher at 3 months and no higher again between 3 and 12 months [18]. The EAU puts spontaneous pregnancy, where it happens, at 6 to 12 months after repair [3]. NICE advises repeating an abnormal semen analysis "ideally 3 months after the initial analysis to allow time for the cycle of spermatozoa formation to be completed" [10]. Our 74-day timeline works the dates out from any start date.

What to do

• If you have been trying for a year, see a GP. Go sooner if your partner is 36 or over, or if either of you has a suspected or known cause, because NICE advises specialist referral straight away in those cases [10].
• Ask for a semen analysis first. A varicocele matters for this decision only alongside semen results that are below the reference limits. Our semen analysis checker puts each value against the WHO 2021 limit.
• Ask whether the varicocele can be felt on examination or was only seen on a scan. The answer changes what every guideline recommends.
• If repair is discussed, ask which technique the unit uses and what its recurrence and hydrocele rates are.
• Ask what the plan is either way, including your partner's side of the assessment. NICE asks that female fertility factors are weighed in the same decision [10].
• If you do have a repair, expect to wait about 3 months before a retest means anything. See when to retest.

Questions

Related

• Low sperm count
• Semen analysis results explained
• How to improve sperm motility
• How to improve sperm morphology
• When to retest
• Total motile sperm count calculator

Sources

1. Alsaikhan B, et al. Epidemiology of varicocele. Asian Journal of Andrology, 2016.
2. Braedel HU, et al. A possible ontogenic etiology for idiopathic left varicocele. Journal of Urology, 1994.
3. European Association of Urology. Guidelines on Sexual and Reproductive Health: Male Infertility, varicocele section.
4. Damsgaard J, et al. Varicocele is associated with impaired semen quality and reproductive hormone levels: a study of 7035 healthy young men from six European countries. European Urology, 2016.
5. World Health Organization Task Force. The influence of varicocele on parameters of fertility in a large group of men presenting to infertility clinics. Fertility and Sterility, 1992.
6. Gorelick JI, Goldstein M. Loss of fertility in men with varicocele. Fertility and Sterility, 1993.
7. Meacham RB, et al. The incidence of varicoceles in the general population when evaluated by physical examination, gray scale sonography and color Doppler sonography. Journal of Urology, 1994.
8. Goldstein M, Eid JF. Elevation of intratesticular and scrotal skin surface temperature in men with varicocele. Journal of Urology, 1989.
9. Persad E, et al. Surgical or radiological treatment for varicoceles in subfertile men. Cochrane Database of Systematic Reviews, 2021.
10. NICE. Fertility problems: assessment and treatment (NG257). March 2026.
11. Agarwal A, et al. Efficacy of varicocelectomy in improving semen parameters: new meta-analytical approach. Urology, 2007.
12. Asafu-Adjei D, et al. Systematic review of the impact of varicocele grade on response to surgical management. Journal of Urology, 2020.
13. Schlegel PN, et al. Diagnosis and treatment of infertility in men: AUA/ASRM guideline part II. Fertility and Sterility, 2021 (with the 2024 AUA amendment).
14. Kohn TP, et al. The effect of subclinical varicocele on pregnancy rates and semen parameters: a systematic review and meta-analysis. Current Urology Reports, 2018.
15. Chen X, et al. Efficacy of varicocelectomy in the treatment of hypogonadism in subfertile males with clinical varicocele: a meta-analysis. Andrologia, 2017.
16. Lira Neto FT, et al. Effect of varicocelectomy on sperm deoxyribonucleic acid fragmentation rates in infertile men with clinical varicocele: a systematic review and meta-analysis. Fertility and Sterility, 2021.
17. Heller CG, Clermont Y. Kinetics of the germinal epithelium in man. Recent Progress in Hormone Research, 1964.
18. Fukuda T, et al. Assessment of time-dependent changes in semen parameters in infertile men after microsurgical varicocelectomy. Urology, 2015.
19. Silay MS, et al. Treatment of varicocele in children and adolescents: a systematic review and meta-analysis from the European Association of Urology/European Society for Paediatric Urology Guidelines Panel. European Urology, 2019.

Correction, 8 October 2026. Source 1's first author is Alsaikhan, not Zini (Zini is the senior author), per the publisher's record and DOAJ. This reverses the 5 October change.