What is pyometra?
Updated By PetymFacts checked against official sources on
Quick answer
Pyometra is a pus-filled infection of the womb in female dogs and cats that have not been spayed. It usually shows a few weeks to months after a heat, with drinking and urinating more, lethargy, poor appetite and sometimes discharge. It is a medical emergency, usually treated by surgery to remove the womb, and spaying prevents it.
Also called womb infection, uterine infection, pyometritis, open pyometra, closed pyometra.
Key facts
- Pyometra is a medical emergency that needs rapid treatment to prevent overwhelming infection and death. American College of Veterinary Surgeons
- Any unspayed female can develop it at any age, but it is most common in pets aged 7 or older. University of Illinois College of Veterinary Medicine
- Signs are more suspicious when they appear a few weeks to months after a heat. University of Illinois College of Veterinary Medicine
- Many dogs and cats have a closed cervix, so there may be no discharge to see. American College of Veterinary Surgeons
- With spaying, survival can be as high as 80 to 100% if the infection responds and the belly is not contaminated. American College of Veterinary Surgeons
- Most dogs and cats spayed early in life will not develop pyometra. American College of Veterinary Surgeons
What are the signs of pyometra?
ACVS says pyometra should be considered in any unspayed female dog that is sick. These signs can be easy to miss.
- Drinking much more water and urinating more. American College of Veterinary Surgeons
- Lethargy, low mood and a poor appetite. American College of Veterinary Surgeons
- Discharge from the vulva, bloody or like pus, on the fur or bedding (only in open pyometra). American College of Veterinary Surgeons
- Vomiting or diarrhoea. American College of Veterinary Surgeons
- A swollen belly. American College of Veterinary Surgeons
- Pale gums. American College of Veterinary Surgeons
What is the difference between open and closed pyometra?
In open pyometra the cervix is open and pus drains out, so an owner may notice discharge. In closed pyometra the cervix is sealed, pus builds up inside the womb and there may be nothing to see. Closed pyometra is more dangerous: the womb can rupture, causing sepsis and death. The University of Illinois puts it plainly: never let the sun set on a pyometra, and for a closed case surgery should happen within 24 hours of diagnosis.
Vets confirm it with blood and urine tests and an X-ray or ultrasound, which usually shows the fluid-filled womb.
How is pyometra treated?
The vet first stabilises the pet with fluids and medicines, then removes the womb and ovaries (an emergency spay). This is the treatment of choice. Medical treatment without surgery is an option only for an open pyometra in a carefully chosen breeding animal; it takes days to work, and the problem can come back with later heats.
Severe sepsis or organ failure makes the outlook worse, and a few pets are left with lasting kidney damage. That is why acting on the first signs matters.
Does spaying prevent pyometra?
Yes. Removing the womb removes the risk, and ACVS notes that spaying also removes the risk of ovarian and uterine cancer and unwanted litters. The University of Illinois advises spaying females not meant for breeding, and says older pets benefit too, not only young ones. Talk to your vet about the right time for your pet.
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Questions owners ask
How long after heat does pyometra happen?
- Signs are most suspicious when they appear a few weeks to months after a heat, according to the University of Illinois College of Veterinary Medicine. Any unspayed female that becomes unwell in the weeks after a heat, especially one drinking much more than usual, should see a vet quickly.
Can a dog survive pyometra without surgery?
- Medical treatment exists, but only for open pyometra in a carefully selected breeding animal, and it takes days to work. The infection can return with later heats. For most pets, and for every closed pyometra, an emergency spay is the treatment vets recommend.
Can cats get pyometra?
- Yes. Unspayed female cats can develop pyometra; ACVS and the University of Illinois describe it in both species. The signs are similar: lethargy, poor appetite, drinking more and sometimes discharge. Spaying prevents it in cats as it does in dogs.
Can a spayed dog get pyometra?
- Rarely. A stump pyometra can develop if some ovarian tissue was left behind after an incomplete spay, or if the pet received certain hormone medicines. A spayed female with signs of a womb infection still needs a vet check.
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Related terms
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Sources
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