Varicocele: aka dealing with the famous "bag of worms"

As a Consultant Urological Surgeon specialising in male fertility and andrology, I have helped many men understand and manage varicoceles. Hearing the term 'varicocele' — or feeling something unusual in your scrotum — can be worrying. This guide brings together up-to-date science and my clinical experience to help you understand what it means, what causes it, and what can be done.

The short answer

A varicocele is a group of enlarged veins in the scrotum, like varicose veins, often described as feeling like a “bag of worms”. It affects about 15% of men, many of whom never notice any symptoms, and it is not a cancer.

Not every varicocele needs treatment. The European and American guidelines recommend repair when three things are true together: the varicocele can be felt on examination, you and your partner are having difficulty conceiving, and your semen results are abnormal. Since March 2026, NICE advises considering treatment in the same situation. Repair is not recommended if your semen analysis is normal, or if the varicocele was found only on a scan.

In teenagers, the deciding measure is testicular growth checked over time. For pain on its own the evidence is thinner, and the decision is one we take together after simpler measures have had a fair trial.

Where repair is appropriate, sperm quality often improves within three to six months, but nobody can promise a pregnancy: the best available review rates the evidence on pregnancy as low certainty. The detail and the sources are set out below, under “What the guidelines say about who should be treated” and “Impact of Varicoceles and Treatment on Fertility & Sexual Function”.

Quick Navigation