Pyometra in Dogs

Table of Contents

Overview | Symptoms | Treatment


"Pyometra in dogs is caused by the buildup of fluids in the uterus. The disease affects female dogs four years of age or older that have not been spayed. Treatment is essential to avoid rare complications such as severe life threatening infection."


Pyometra is a disease in female dogs that have not been spayed. It usually affects dogs who are four years of age or older with most dogs showing signs of the disease at 9 years old. Approximately 23% of female dogs over age 10 have the disease.

Pyometra is dogs is caused by the hormones estrogen and progesterone. If the uterus produces too much progesterone cysts in the uterus start to form in the uterine lining. These cysts release fluid which thickens the walls of the uterus. As the uterus enlarges the liquid leaks out of the dog. The liquid also causes bacteria to form. As the disease worsens the cervix closes keeping the liquid inside the body. In very rare cases the uterus ruptures into the abdomen causing death.

Treatment choices include surgery (spaying) or medications. When treated with medications there is a high likelihood of reoccurrence, but a necessary approach if you are breeding. Spaying female dogs before the age of 6 months can prevent the disease.

Breeds that are Predisposed to Pyometra

Certain breeds are more likely to get pyometra in dogs than others:

  • Bernese
  • Mountain dog
  • Rottweiler
  • Rough-haired Collie,
  • Cavalier
  • King Charles Spaniel
  • Golden Retriever

Symptoms of Pyometra in Dogs

Symptoms are associated with the kidneys working harder to remove toxins that are building up in the body. They include:

  • Excessive thirst (polydipsia)
  • Frequent urination (polyuria)

Diagnosis of Pyometra in Dogs

Ultrasound and X-Rays are used to determine a diagnosis. If a female dog is pregnant under 40 days it is possible to diagnose pyometra when in fact your dog is pregnant.

Treatment of Pyometra in Dogs

Options for treatment include surgery (Ovariohysterectomy) and medications. Surgery is recommended for older dogs that are not going to be breeding. The operation removes both the uterus and the ovaries. Medications are a more conservative option, although studies show that 20% of dogs will suffer from the disease again.

If your dog was in heat more than 2.5 months ago then the drug Prostaglandin is used to promote the opening of the cervix and contractions.

If the last heat occurred more than 2.5 months ago, the bitches are treated with Prostaglandin (Dinolytic is the brand name) to encourage the cervix to open and contractions of the muscular wall of the uterus (myometrium). There is a low risk of side effects. Treatment lasts for 5 to 8 days. Your veterinarian may also prescribe an antibiotic to avoid bacterial infection.

If it is under 2.5 months since your dog was in heat then the drugs Aglépristone (to open the cervix - Alizine, Virbac are brand names) and Prostaglandin (helps to prevent bacteria from forming - Dinolytic is the brand name) are used. Antibiotics may also be prescribed to prevent or treat bacterial infection.


Canine Pyometra: New Approaches to an old Disease
Susi Arnold, Prof. Dr. med. vet.,
Iris Reichler, Dr. med. vet.
Madeleine Hubler, Dr. med. vet.
Clinic for Reproductive Medicine
University of Zurich

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