Recovery & aftercare

Vasectomy side effects and warning signs to know

Edited by Maya Ellison, Health Editor · Written by the Vasectomy Cost Guide Editorial Team · Updated 8 November 2026 · 5 min read

Most vasectomy side effects are short-lived: swelling, bruising, a dull ache and a small amount of spotting. They are expected, they settle, and they do not mean something has gone wrong. A smaller number of men develop complications that need treatment, and a very small number develop chronic scrotal pain.

Knowing the difference between normal recovery and a warning sign is the point of this guide. It is not a substitute for your clinic’s aftercare instructions, which take precedence.

Common side effects

Swelling. The scrotum swells after the procedure, often peaking around day two. It should improve after that. Ice, support and rest reduce it.

Bruising. Bruising can spread into the groin and down the scrotum, and it often looks worse on day two or three than on day one. It fades over one to two weeks.

Pain and ache. A dull ache in the scrotum and groin is normal for several days. Ordinary painkillers usually manage it. Sharp or worsening pain is not normal.

Spotting. A small amount of blood-stained discharge from the puncture or incision is common for a day or two.

A small lump. A firm, pea-sized lump at the site is often a sperm granuloma — a small collection of sperm that has leaked and caused a local reaction. It is usually harmless and settles over weeks or months.

Tiredness. Some men feel tired for a day or two, partly from the anaesthetic and partly from the procedure itself.

Less common complications

Infection. Signs are spreading redness, warmth, pus, a bad smell or fever. It is uncommon and usually treatable with antibiotics. Call the clinic.

Haematoma. A collection of blood in the scrotum causes a hard, painful swelling. It can look dramatic. Most settle with rest and support, but a large one should be assessed.

Sperm granuloma. As above, usually harmless. A persistent or painful one can be reviewed.

Chronic scrotal pain. Pain lasting more than three months after the procedure is sometimes called post-vasectomy pain syndrome. Estimates vary, but it is uncommon — often described as affecting around 1% to 2% of men, with some studies reporting higher rates of mild discomfort. It can range from an occasional ache to pain that affects daily life. If it happens, it is treatable in many cases, but it can be persistent.

Antibody formation. The body may develop antibodies against sperm after a vasectomy. This is common and is not usually harmful; it matters mainly if reversal is attempted.

Recanalisation. The ends of the vas can rejoin, usually early, which is why the semen analysis matters. Late recanalisation is rare.

What is not a side effect

A vasectomy does not cause:

• weight gain or loss;
• hair loss;
• a change in testosterone;
• erectile dysfunction;
• a change in the volume or appearance of ejaculate;
• prostate cancer (the evidence does not support a causal link);
• heart disease;
• a change in voice or masculine characteristics.

If you experience one of these after a vasectomy, it is not caused by the blocked vas deferens, and it is worth discussing with a doctor for its own sake.

Warning signs: call the clinic the same day

• Fever above 38°C (100.4°F).
• Spreading redness, warmth or pus at the site.
• Severe or rapidly increasing swelling.
• Bleeding that does not stop with gentle pressure.
• Difficulty passing urine.
• Pain that is getting worse after the first week rather than better.
• A lump that is growing quickly or is very painful.

These are uncommon, but they are the reason the clinic gives you an after-hours number. Use it rather than waiting for a scheduled review.

How long side effects last

If a symptom is outside these windows and not improving, ask the clinic.

Reducing the risk of complications

• Follow the aftercare instructions, especially rest and support in the first 48 hours.
• Do not return to heavy lifting or sport early.
• Keep the wound clean and dry for the first 24 hours.
• Take painkillers as directed rather than doubling up.
• Attend the follow-up and the semen analysis.
• Tell the clinic about bleeding disorders or blood-thinning medication before the procedure.

None of these guarantees a complication-free recovery, but they reduce the avoidable ones.

When to seek urgent care

Go to an emergency department or call emergency services if you have:

• severe pain with a swollen, hard scrotum that came on suddenly;
• heavy bleeding that will not stop;
• signs of sepsis — high fever, confusion, rapid breathing, a rapid heartbeat;
• inability to pass urine.

These are rare after a vasectomy, but they are medical emergencies, not things to wait on.

The bottom line

Most vasectomy side effects are mild, expected and short-lived. Infection, haematoma and chronic scrotal pain are the complications to know about, and the warning signs above are the ones that need a same-day call. If something feels wrong, contact the clinic rather than searching for reassurance online.

Frequently asked questions

Is swelling normal after a vasectomy? Yes, in the first few days. Rapidly increasing swelling or swelling with fever is not and needs a call.

Can a vasectomy cause long-term pain? A small percentage of men develop chronic scrotal pain lasting more than three months. It is uncommon but real, and it is worth discussing before the procedure.

Does a vasectomy increase cancer risk? The evidence does not support a causal link with prostate cancer. Discuss any concerns with your clinician.

How long does bruising last? Usually one to two weeks. It can look worse before it looks better.

Can I get an infection after a vasectomy? It is uncommon but possible. Signs are redness, warmth, pus and fever — call the clinic.

Sources

1. mayoclinic.org/tests-procedures/vasectomy/about/pac-20384580
2. nhs.uk/contraception/methods-of-contraception/vasectomy-male-sterilisation
3. urologyhealth.org/urology-a-z/v/vasectomy
4. auanet.org/guidelines-and-quality/guidelines/vasectomy-guideline