What is Pyometra in Cats and Dogs? A Vet Emergency
Pyometra is a serious infection of the uterus (womb), often called a womb infection, that affects unneutered female dogs and cats. The uterus fills with infected fluid, causing pets to become seriously unwell. Without prompt veterinary treatment, pyometra can quickly become life-threatening.
Pyometra affects both dogs and cats, although it is much more common in dogs. The condition most often affects middle-aged and older pets, but younger unneutered females can also develop it.
There are two main types of pyometra:
Open pyometra – the cervix remains open, allowing infected discharge to drain from the vulva.
Closed pyometra – the cervix is closed, trapping the infection inside the uterus. There may be no visible discharge, making this form more difficult to recognise.
Pyometra is a veterinary emergency. Early diagnosis and treatment offer the best chance of a successful recovery.
Pyometra in Cats and Dogs - Symptoms, Treatment, Prevention
The symptoms of pyometra can vary but affected dogs and cats often become generally unwell. Signs may develop gradually or worsen quickly.
Common symptoms include:
Vaginal discharge containing pus, blood or a foul-smelling fluid (in open pyometra)
A swollen or painful abdomen, particularly in closed pyometra
Some pets with closed pyometra have no visible discharge, making the condition more difficult to recognise. Cats often show more subtle signs than dogs, so the condition can be harder to recognise.
Because pyometra is a serious infection, any unneutered female dog or cat that becomes unusually unwell should be examined by a vet promptly.
Pyometra is a veterinary emergency and should not be left to see if it improves.
Contact your vet as soon as possible if your unneutered female dog or cat is unwell, especially if they have vaginal discharge, are drinking more than usual, seem unusually tired or have a swollen abdomen. Even without a visible discharge, pyometra can still be present.
Prompt treatment gives the best chance of a successful recovery and helps reduce the risk of serious complications.
Your vet will examine your dog or cat and discuss their symptoms and medical history.
An ultrasound scan is usually the best way to diagnose pyometra because it allows your vet to examine the uterus for changes that are typical of the condition.
Blood tests are also commonly recommended to assess your pet's overall health and help plan the safest treatment.
Together, these tests help confirm the diagnosis and guide treatment.
Surgery to remove the infected uterus and ovaries (an emergency neutering procedure) is the most effective treatment for pyometra and is recommended for most pets.
Before surgery, your pet may need intravenous fluids, pain relief and antibiotics to help stabilise their condition. Most pets will need to stay in hospital for treatment and monitoring.
In some cases, medical treatment may be considered, but this is not suitable for every pet and carries a higher risk of the condition returning.
Prompt treatment offers the best chance of a successful recovery.
The best way to prevent pyometra is to have your dog or cat neutered. Removing the uterus and ovaries eliminates the risk of developing this condition.
If you are considering neutering your pet, your vet can advise you on the most appropriate timing based on their age, breed and overall health.
Further reading: Guide to Neutering Your Cat, Guide to Neutering Your Dog
Most pets recover well from pyometra when they receive prompt treatment. Recovery is generally quicker and the risk of complications is lower when the condition is diagnosed early.
Without treatment, pyometra can become life-threatening. If you think your pet may have pyometra, contact your vet as soon as possible.
Written by Gill Burkhill, Veterinary Surgeon, Animal Trust Vets CIC | Published July 2026 | Review date July 2029 | This advice is for UK pets only and is not a replacement for seeing a vet