Varicocele is one of the most common — and most commonly overlooked — conditions affecting men’s reproductive health. If you’ve noticed discomfort, swelling, or a “bag of worms” feeling in your scrotum, or you’ve been told a varicocele may be affecting your fertility, here’s what you need to know.
What Is a Varicocele?
A varicocele is an abnormal enlargement of the veins within the scrotum — essentially, a varicose vein of the testicle. It happens when valves inside these veins stop working properly, allowing blood to pool and the veins to widen. Varicoceles are extremely common, affecting roughly 15 out of every 100 men, and they occur far more often on the left side than the right due to the anatomy of the veins draining that testicle.
Most varicoceles develop during puberty and are often harmless, causing no symptoms at all. But for some men, a varicocele causes real discomfort — and it’s one of the most common reversible causes of male infertility, found in up to 35–40% of men being evaluated for infertility.
Common Symptoms of Varicocele
- A dull ache or sharp pain in the testicle, often on the left side
- Discomfort that worsens as the day progresses, or with standing and physical activity
- A feeling of heaviness or dragging in the scrotum
- Visibly enlarged or twisted veins, sometimes described as feeling like a “bag of worms”
- Reduced sperm count, motility, or quality on semen analysis
- In adolescents, a smaller testicle on the affected side (testicular atrophy)
Many men with a varicocele have no symptoms at all and only discover it during a physical exam or a fertility workup. If you notice testicular discomfort that worsens throughout the day or with activity, it’s worth having it evaluated.
What Causes a Varicocele?
Varicoceles form when the valves inside the veins of the spermatic cord fail to function properly, allowing blood to flow backward and pool instead of returning efficiently to the heart. This backup increases pressure and heat within the scrotum, which is thought to be part of why varicoceles can impair sperm production — sperm develops best at temperatures slightly below normal body temperature, and the added heat from pooled blood can interfere with that process.
How Is a Varicocele Diagnosed?
Diagnosis typically starts with a physical exam, which may be performed both lying down and standing, sometimes while bearing down to make the varicocele more apparent. A scrotal ultrasound is often used to confirm the diagnosis, evaluate the testicles, and assess the size of the varicocele. If fertility is a concern, blood work to check hormone levels and a semen analysis may also be recommended.
Do All Varicoceles Need Treatment?
Not necessarily. A varicocele that isn’t causing pain, discomfort, or fertility concerns can often simply be monitored. Treatment becomes worth considering when a varicocele causes persistent discomfort, when it’s linked to abnormal semen parameters in a man trying to conceive, or when it appears to be affecting testicular development in a younger patient.
If you’re experiencing varicocele symptoms in the Kansas City area, learn more about your treatment options in our companion post, Varicocele Treatment Options: Embolization vs. Surgery, or visit our Varicocele Embolization page to learn how MIVA Medical treats this condition without surgery. Book a consultation to get evaluated.