What is a pyometra?

Pyometra is an infection of the uterus.  It is an emergency, life-threatening condition that commonly occurs in older female dogs that have not been speyed.

Each time an entire female dog has a heat (or season), she undergoes all of the hormonal changes associated with pregnancy, regardless of whether she becomes pregnant or not.  These hormonal changes increase the risk of an infection developing in the uterus following each subsequent heat.

Some dogs can have an underlying uterine condition (Cystic Endometrial Hyperplasia) that makes them more prone to developing a pyometra. Some hormone injections used to stop or delay a heat can also increase the risk of developing a pyometra.


What are the signs of a pyometra?

A pyometra more commonly develops in older female dogs (over 6 years of age), but can occur at any age.  Usually signs develop about 4-6 weeks following her being on heat.  In some cases she can appear to have a prolonged season.

Early signs you may notice:

  • Off-colour, lethargic, depressed
  • Reduced appetite
  • Drinking more than usual (urinating more)
  • Licking at her back end more than usual
  • Pus (yellow/brown/red discharge) from her vulva

These signs can progress to:

  • Vomiting
  • Swollen abdomen
  • Collapse

If left untreated she will rapidly deteriorate and death due to septic shock can occur.


Diagnosis and treatment of pyometra

Your vet will likely be quite suspicious of a pyometra based on the description her symptoms and following a thorough examination of your pet.

An ultrasound of her abdomen will often reveal an abnormally large, fluid-filled uterus – this will help confirm a diagnosis of a pyometra.

The best treatment is immediate surgery to remove the infected uterus. The operation is essentially the same as a routine spey procedure, however there is much greater risk of complications as the infected uterus is very fragile and the operation is being carried out on a sick animal.  One of the main complications is rupture of the uterus into the abdomen, prior to, or during surgery.  This can spread the infection and makes it much more difficult to successfully treat.

She will also be given an intravenous drip, antibiotics and pain relief to stabilise and support her through the surgery.



If you do not plan to breed from your dog, or she is having no further litters of puppies, speying her will prevent a pyometra from developing.

If your female dog is not speyed, it is important to be familiar with the signs of a pyometra. If you notice her displaying any of these symptoms following a recent heat, contact your vet immediately. Early treatment will give her the best possible chance of a successful speedy recovery!