Uterine inflammation in dogs, also known as pyometra, is one of the most common ailments among bitches. This condition occurs in a specific phase of the bitch's hormonal cycle, and the inflammation is most common in older bitches. Read on to dive deeper into the topic uterine inflammation in dogs, and learn about the causes behind the condition, symptoms to watch out for, and available treatment options.

Table of contents

What is uterine inflammation in dogs

Uterine inflammation is a serious condition that can affect bitches that have not been spayed. In order to be able to recognize the symptoms in time, it is important that you as a dog owner familiarize yourself with the disorder. First of all, we divide uterine inflammation in dogs into two different categories. 

Open pyometra 

In this type of uterine inflammation, pus or pain is secreted through the genital opening. This indicates that the cervix is ​​open, and there is therefore a passage through which labor is released. Often owners notice that the dog has an abnormal discharge that differs from the normal discharge during the heat.

Closed pyometra 

When the cervix is ​​closed, there will be no visible discharge via the genital opening. This makes this form of uterine inflammation more difficult to detect, and can therefore often be more serious for the affected dog. Closed pyometra is the most acute form of uterine inflammation and can quickly become life-threatening.

Causes of uterine inflammation

The main cause of uterine inflammation is hormonal changes during the dog's reproductive cycle. After each period, regardless of whether the bitch is mated or not, the ovaries (ovaries) produce the hormone progesterone. Among other things, this hormone contributes to the growth and activity of glands in the bitch's uterus. During the heat, estrogen is also produced, one of the bitches' sex hormones. Estrogen increases the number of receptors for progesterone, so that this hormone has an additional effect on the uterus after menstruation. This plays an important role in the development of pyometra. As a result, some dogs may experience the accumulation of fluid and the formation of cysts in the uterine cavity, which can later develop into an inflammation of the uterus.

Some dogs then experience an accumulation of fluid and cyst formation in the uterine cavity, and eventually inflammation. ​​Usually, uterine inflammation in dogs develops in the period 1-12 weeks after term. Eventually, the dog is strongly affected and experiences a systemic state of intoxication.

Who is in the risk group for uterine inflammation?

As I said, uterine inflammation can develop in all non-neutered bitches, i.e. dogs that have not had their uterus and ovaries removed. Nevertheless, it is most common in older dogs that have had several periods. Every year, however, a few cases of uterine inflammation are seen in young dogs aged 1-3 years.

No specific breeds have been shown to have a hereditary predisposition to developing uterine inflammation. However, hormone injections used to delay heat and thus affect the bitch's normal cycle can increase the risk of uterine inflammation in dogs. Bitches that are pregnant, but experience that the puppies die in the fetal stage, also have a somewhat increased risk of developing this disease.

Symptoms of uterine inflammation 

There are several indicators that may indicate that a dog has developed uterine inflammation. These include:

Symptoms of uterine inflammation include:

  • Discharge with bloody pus from the genital opening (in cases of open pyometra)
  • Excessive licking of the body
  • Increased thirst and more frequent urination
  • General lassitude
  • Decreased appetite
  • Fever
  • Vomit

Many dogs will show changes in their general behavior and may appear depressed. Bitches often have a reduced appetite and some may even vomit. At the same time, several dogs will drink more water than usual. Increased thirst is a typical early symptom of beginning uterine inflammation. The bacteria produce waste substances and poisons (toxins) which are spread through the blood over time, which can lead to systemic poisoning of the dog.

Some dogs may develop a fever and appear very lethargic. Often the owner can also notice that the dog licks itself a lot, and there can be a visible discharge of pus from the genital opening. 

As mentioned, closed pyometra can develop very quickly, as pus accumulates inside the abdominal cavity. This leads to rapid and serious illness in the bitch and the condition can be life-threatening. In extreme cases, the uterus can even rupture, with subsequent accumulation of pus in the abdominal cavity. If you as a dog owner suspect uterine inflammation or are unsure of your dog's general condition, you should contact a vet immediately. This is not a condition dogs can recover from on their own.

If you observe any of the above symptoms in your dog, it is important to seek veterinary help immediately. In our veterinary clinic in Larvik, we always prioritize acute cases

Treatment of uterine inflammation 

Treating uterine inflammation usually requires urgent medical intervention. The vet will assess the dog's condition on the spot and choose the most appropriate treatment. Usually this involves surgical removal of the uterus, also known as ovariohysterectomy. This is an effective way to both treat the condition and prevent recurrence.


Uterine inflammation in dogs is a serious condition that can develop into life-threatening. Understanding the causes, symptoms and treatment options is important to ensure early diagnosis and prompt treatment. If you suspect that your dog may have uterine inflammation, contact your vet immediately. At A-Vet, we are always ready to offer our expertise both for advice and treatment of your pet! 

Uterine inflammation in dogs. Illustration of a dog with and without pyometra / uterine inflammation.
Illustration of uterine inflammation / pyomtra in dogs - Source: pesa.org.uk
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Elisabeth is a veterinarian and authorized ophthalmologist with specialization in eye surgery, as well as further training in internal medicine, general surgery, oral surgery and ultrasound from the European School for Advanced Veterinary Studies in Toulouse.