Varicocele and Fertility

The Basics: What's Happening Anatomically

A varicocele is an enlargement of the veins within the loose bag of skin that holds your testicles (the pampiniform plexus). Think of it like varicose veins, but in the scrotum instead of the legs. The valves in these veins that normally keep blood flowing upward toward the heart stop working properly, allowing blood to pool and the veins to dilate.

Varicoceles occur almost exclusively on the left side (about 85% of cases) due to anatomical differences in how the left testicular vein drains compared to the right. However, even a left-sided varicocele can affect both testicles because the elevated temperature and pressure affect the entire scrotal environment.

How Varicoceles Damage Sperm

Your testicles hang outside your body for a reason — they need to be 2-4°C cooler than core body temperature for optimal sperm production. Varicoceles disrupt this temperature regulation through several mechanisms:

• Heat damage: Pooled blood raises scrotal temperature, impairing the enzymes involved in sperm production.
• Oxidative stress: The stagnant blood creates a high-oxidative-stress environment that damages sperm DNA.
• Hormonal disruption: Adrenal metabolites that should be filtered away can flow backward toward the testes, disrupting local hormone production.
• Pressure effects: Increased venous pressure reduces the oxygen supply to Leydig cells (which produce testosterone) and Sertoli cells (which nurture developing sperm).

Do You Have One? How to Tell

Many varicoceles are asymptomatic, discovered only during fertility workups. When symptoms occur, they typically include:

• A dull, aching pain in the testicle that worsens with standing or physical activity and improves lying down
• A visible or palpable mass above the testicle (often described as feeling like a "bag of worms")
• One testicle noticeably smaller than the other (testicular atrophy)
• Discomfort that increases over the course of the day

Does Varicocele Repair Actually Help?

This is the million-dollar question, and the answer is nuanced. A 2014 Cochrane review was skeptical about the benefits of varicocele repair for fertility, but more recent and better-designed studies have shown meaningful improvements.

A 2016 meta-analysis in European Urology found that varicocelectomy (surgical repair) resulted in significant improvements in sperm concentration, motility, and morphology. More importantly, pregnancy rates improved from approximately 27% in untreated couples to 45% in couples where the varicocele was repaired.

Who Benefits Most from Surgery?

• Best candidates: Men with clinically palpable varicoceles AND abnormal semen parameters. This combination shows the strongest surgical benefit.
• Moderate benefit: Men with subclinical varicoceles (only visible on ultrasound) and borderline semen quality.
• Minimal benefit: Men with varicoceles but normal semen parameters — surgery in this group doesn't improve outcomes significantly.
• Consider IVF instead: If the female partner is over 35 or has her own fertility factors, the 3-6 month recovery time after surgery may not be worth the wait. Discuss IVF/ICSI as an alternative.

Lifestyle Support While You Wait

Whether you're pursuing surgery, waiting for results, or managing conservatively, these evidence-based strategies support sperm health in the presence of a varicocele:

The Bottom Line

Varicoceles are incredibly common and often go undiagnosed because many men don't know to look for them. If you're TTC and have abnormal semen analysis results, a varicocele evaluation should be part of your workup. It's a physical exam and ultrasound — straightforward and non-invasive.

For men with clinical varicoceles and impaired semen parameters, surgical repair has strong evidence behind it, with studies showing pregnancy rates nearly doubling after treatment. For those waiting for surgery or managing conservatively, antioxidant supplementation and temperature management can provide meaningful support.