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Complications - Mumps

Sometimes mumps can cause complications (problems). While they can be worrying, they are rarely serious. They usually go away as the infection clears up.

Complications happen more often among people who have not had the vaccine.

You are more likely to have milder symptoms and fewer complications if you are vaccinated.

Swollen testicle

About 1 in 3 unvaccinated males who get mumps after puberty gets a swollen testicle (orchitis). The swelling usually comes on suddenly and can be painful. It often affects just 1 testicle. The testicle may feel warm and tender.

The swelling usually begins 4 to 8 days after the parotid gland swells - but it can take up to 6 weeks.

You can do some things to help ease the pain.


  • hold a warm or cool face cloth or towel to the swollen testicle

  • wear supportive underwear

  • take painkillers such as paracetamol or ibuprofen

Non-urgent advice: Contact your GP if:

the pain is severe - they may prescribe stronger painkillers

What we mean by severe pain

Severe pain:

  • always there and so bad it's hard to think or talk
  • you cannot sleep
  • it's very hard to move, get out of bed, go to the bathroom, wash or dress
  • you cannot work due to the pain

Moderate pain:

  • always there
  • makes it hard to concentrate or sleep
  • you can manage to get up, wash or dress

Mild pain:

  • comes and goes
  • is annoying but does not stop you from doing things like going to work

Some people who get swollen testicles after mumps notice some shrinkage of their testicles, after the swelling has eased. In a small number, this can cause reduced fertility.

Swollen ovaries

About 1 in 14 unvaccinated females who get mumps after puberty has swelling of the ovaries (oophoritis).

This can cause:

The symptoms of oophoritis usually ease once the mumps infection has passed.


About 1 in 25 unvaccinated people with mumps get short-term swelling of the pancreas (acute pancreatitis). This can cause a sudden pain in the centre of your tummy (abdomen).

Other symptoms include:

  • nausea (feeling sick) or vomiting (getting sick)
  • diarrhoea
  • loss of appetite
  • high temperature of 38 degrees Celsius or higher
  • tenderness in your tummy (abdomen)
  • jaundice (yellowing of the skin and whites of the eyes)

Pancreatitis associated with mumps is usually mild. But you may be admitted to hospital for treatment until your pancreas recovers.

Viral meningitis

You can get viral meningitis if the mumps virus spreads into the outer protective layer of the brain (the meninges). This happens in fewer than 1 in 10 unvaccinated people with mumps.

The risk of serious complications from viral meningitis is low.

Common symptoms include:

  • mild sensitivity to light
  • neck stiffness
  • headaches

These symptoms usually pass within 14 days.

Emergency action required: Call 112 or 999 or go to your nearest emergency department (ED) if:

  • your or someone else's symptoms are severe

Rare complications of mumps

The mumps virus can cause rare but sometimes serious complications.

These include a brain infection called encephalitis. Encephalitis can be fatal and needs to be treated in an intensive care unit in hospital.

Some people with mumps experience temporary hearing loss.

Permanent hearing loss is very rare, with cases thought to be about 1 in 20,000.

Pregnancy and mumps

In the past, mumps was linked to a higher risk of miscarriage. But there's little evidence to support this.

If you are pregnant, you should avoid close contact with someone who has mumps.

Do not get the mumps (MMR) vaccine while you are pregnant.

If you get the vaccine, avoid getting pregnant for 1 month afterwards.

If you're pregnant and concerned about mumps, talk to your obstetrician or midwife.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 14 April 2024
Next review due: 14 April 2027

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.