Pyometra: A Serious Uterine Infection in Dogs and Cats

Intact female dogs and cats are susceptible to several conditions that spayed dogs and cats are not. Pyometra is one of these conditions.

What Is Canine and/or Feline Pyometra?

Pyometra: A Serious Uterine Infection in Dogs and Cats Canine and feline pyometra is severe infection within the uterus of the dog and cat, respectively. Pyometra only occurs in intact female dogs and cats. In spayed dogs and cats, the uterus is often (but not always) removed as part of the surgical process and thus is not able to become infected. In addition, the hormonal changes that occur routinely as part of the reproductive cycle do not occur in spayed female dogs and cats. These hormonal changes are the reason that pyometra develops in dogs and cats.

What Are the Symptoms of Pyometra in Dogs and Cats?

Dogs and cats with pyometra may or may not have a foul-smelling vaginal discharge, depending on whether the cervix is open or closed. The discharge may appear bloody or may look more like pus. When present, the discharge makes the diagnosis of pyometra much easier.


Other symptoms that may be seen with canine and feline pyometra include:

  • vomiting
  • depression
  • fever
  • depressed or absent appetite
  • dehydration
  • increased thirst
  • increase in urine production

Dogs and cats affected by pyometra can be profoundly ill. Pyometra can be a fatal condition, especially if left untreated. This is because as the infection develops in the uterus, bacteria and toxins present in the uterus start to leak out into the blood stream causing septicemia, which affects not only the uterine tract but the entire body.

Diagnosing Pyometra in Your Dog or Cat

A vaginal discharge in an intact female dog or cat that has recently been in heat is highly suggestive of pyometra. This is usually easily spotted during a physical examination. However, other diagnostic tests may be necessary to confirm the diagnosis.

In addition, not all pets with pyometra will have a vaginal discharge. In this case, other laboratory testing will be necessary if the initial physical examination findings and history of the dog or cat indicate the possibility of a pyometra.

Diagnostic tests that your veterinarian may recommend include:

  • a blood screen consisting of a complete blood cell count and chemistry profile. Changes in the blood screen with pyometra are usually consistent with those seen with infection.
  • a radiograph (x-ray) of the abdomen. The radiograph may reveal an enlarged fluid-filled uterus, but radiograph results can be inconclusive as well.
  • abdominal ultrasonography (an ultrasound study of the abdomen). The ultrasound study will usually reveal an enlarged fluid-filled uterus.

Treating Canine and Feline Pyometra

If your dog or cat is diagnosed with pyometra, the treatment of choice is surgical removal of the infected reproductive tract. However, it is important to remember that dogs and cats suffering from pyometra are often not good surgical candidates. For this reason, the surgery is usually much more dangerous than performing a normal routine spay. Supportive care before, during and the surgery will be necessary and should include intravenous fluid therapy, antibiotics, and pain medication. Careful monitoring during and after the surgery is necessary as well.

In cases where surgical removal of the infected uterus is not practical or possible, antibiotics can be attempted. However, they are not always successful. In many cases, the antibiotics may provide temporary improvement, with a recurrence of symptoms of a later date.

Hormonal therapy using prostaglandins can be attempted for those dogs whose reproductive status must be preserved for breeding. However, the success rate is less than optimal with this treatment.

There are several good reasons to spay your female dog or cat. However, the ability to prevent your pet from developing pyometra is one of the most important reasons. Pyometra is a risk that can be avoided all together in both the canine and the feline pet when the pet is spayed.

Photo Courtesy of desmorider/

About Lorie Huston, DVM

Lorie Huston, DVM has written 88 posts in this blog.

Lorie Huston is a veterinarian with 20+ years of experience with dogs and cats. She is also a talented free-lance author and blogger and has contributed to numerous publications, including Pet Sitter's WORLD, FIDOFriendly, Dancing Dog Blog, Dawg Business and many others. Lorie is the featured pet care writer at, a contributing writer in Dog and Cat Diseases and Conditions at and the National Pet Health Examiner at In addition, she is a host of the popular podcast/review site, Animal Cafe.



  1. Nicole says

    If veterinarians didn’t charge the equivalent to a couple of mortgage payments to perform the procedure I`m sure more people would have their pets spayed or neutered.

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