Symptoms and Surgery for Pyometra in Dogs

UrinaryDiseasesMeongsiljang Veterinary Advisory Board

Our veterinary advisory team has compiled this guide covering the causes of pyometra in dogs, the differences between open and closed forms, and the surgical procedure and post-operative care.

What is Pyometra in Dogs?

A veterinarian gently palpating the abdomen of a female puppy at the animal hospital.

Pyometra is a condition in which bacteria infect the uterus, causing it to fill with pus. It primarily affects intact female dogs and, if left untreated, can lead to uterine rupture or sepsis. The condition most commonly develops one to two months after a heat cycle, and the risk increases with age. According to veterinary textbooks, pyometra is known to occur more frequently in intact females of middle age and older. Therefore, dogs fitting this profile are advised to undergo regular veterinary check-ups and be closely monitored for any abnormal symptoms following each heat cycle.

Causes of Pyometra

The primary cause of pyometra is hormonal changes. After each heat cycle, elevated levels of the hormone progesterone cause the uterine lining to thicken, creating an environment conducive to bacterial growth. If bacteria such as Escherichia coli enter the uterus through the vulva, infection can begin. Because the uterine lining thickens progressively with repeated heat cycles, older dogs are at greater risk. Additionally, a history of administering hormonal medications, such as heat suppressants, can increase the likelihood of developing the condition.

Checklist of Main Symptoms of Pyometra

Pyometra is classified into open and closed forms, with symptoms varying by type.

Vulvar discharge: Seen in the open form, characterized by a brown or yellow discharge often mixed with blood.

Excessive thirst: A common systemic symptom as pyometra progresses, marked by abnormally high water intake (polydipsia).

Increased urination: The frequency and volume of urination increase in proportion to the excessive drinking.

Loss of appetite and lethargy: As the infection worsens, the pet may refuse food and show little desire to move.

Abdominal distension: In the closed form, the abdomen swells because pus cannot drain externally.

A female puppy lying listlessly with a water bowl placed beside her.

Go to the Vet Immediately if You See These Symptoms

Closed pyometra occurs when pus cannot drain from the uterus, which can lead to uterine rupture. If the uterus ruptures, the infection can spread to the abdominal cavity, causing peritonitis. If your pet suddenly becomes lethargic without any vaginal discharge, shows severe abdominal pain when touched, has pale gums, or develops a fever, seek veterinary care immediately. Untreated pyometra can be life-threatening, so it is crucial to visit a veterinarian as soon as you notice these signs.

Diagnostic Methods for Pyometra

Veterinary clinics typically diagnose pyometra by combining several diagnostic tests.

Blood tests: White blood cell counts are often significantly elevated. Kidney and liver function values are also checked.

Abdominal ultrasound: This is a useful imaging test that allows direct visualization of the fluid-filled uterus located between the bladder and the colon.

X-rays: These are used to identify an enlarged uterus within the abdominal cavity and, along with abdominal ultrasound, are standard imaging tools for diagnosing pyometra.

Providing your veterinarian with detailed information about your pet’s heat cycle history and current symptoms helps ensure a faster and more accurate diagnosis.

Treatment for Pyometra – Surgery and Medication

The most definitive treatment for pyometra is an ovariohysterectomy, a surgery that removes the infected uterus and ovaries, offering the highest cure rate. Before surgery, intravenous fluids are administered to correct dehydration, and antibiotics are given to stabilize the infection. According to veterinary surgical textbooks, early surgery generally leads to a good prognosis; however, the risk increases if uterine rupture or sepsis has already progressed. If breeding is planned, medical management may be considered, but due to the high recurrence rate, thorough consultation with a veterinarian is essential.

A veterinarian performing an ovariohysterectomy on a dog in the operating room.

Post-Operative Care Points

Proper post-operative care is essential for a smooth recovery.

Protect the surgical site: Use an Elizabethan collar to prevent your pet from licking or scratching the incision. Sutures are typically removed after 10–14 days.

Administer antibiotics as prescribed: Ensure your pet completes the full course of prescribed antibiotics. Do not stop medication midway, even if symptoms appear to improve.

Restrict activity: Avoid vigorous exercise or walks for 1–2 weeks after surgery, and allow your pet to rest adequately.

Manage diet: On the day of surgery, start with small amounts of water and soft food. Gradually return to your pet’s regular diet as their appetite returns.

A puppy recovering from surgery, resting comfortably at home while wearing a neck brace.

Breed-Specific Precautions and Prevention

Pyometra can be prevented in nearly 100% of cases through spaying. If you have no plans to breed your dog, consult with your veterinarian to determine the appropriate timing for the procedure. Since all intact female dogs, particularly older ones, are at risk, it is crucial to carefully monitor for any abnormal symptoms after heat cycles and schedule regular veterinary check-ups, especially for middle-aged and older intact females.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

How much does surgery for pyometra cost?

The cost varies depending on the clinic, your dog’s size, and their specific condition, so it’s difficult to provide a general estimate. For the most accurate information, I recommend consulting directly with a nearby veterinary clinic.

Can a spayed dog still get pyometra?

If your pet has undergone a complete spay surgery, which involves the removal of both the ovaries and the uterus, they will not develop pyometra. In very rare cases where some uterine tissue remains, it could potentially occur, but this is extremely uncommon.

Is surgery always necessary for pyometra?

Surgery is the most effective and safest treatment option. While medication can be used, it has a high recurrence rate, and in cases of closed-angle glaucoma, drug therapy can be risky, so it's essential to consult with your veterinarian.

Can pyometra be transmitted to other dogs?

Pyometra is a condition caused by hormonal changes and bacterial infection, so it is not contagious to other dogs.

How long does the recovery period last after surgery for pyometra?

Sutures are typically removed 10 to 14 days after surgery, and your pet can usually resume normal daily activities within 2 to 4 weeks. However, if sepsis was present, recovery may take longer.

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References

[1] Fossum TW. Surgery of the Reproductive and Genital Systems. In: Small Animal Surgery. 5th ed. Elsevier; 2019.

[2] Nelson RW, Couto CG. Disorders of the Canine Female Reproductive Tract. In: Small Animal Internal Medicine. 6th ed. Elsevier; 2020.

[3] Hagman R. Pyometra in Small Animals 2.0. Vet Clin North Am Small Anim Pract. 2022;52(3):631-657.

[4] Jitpean S, Hagman R, Ström Holst B, et al. Outcome of pyometra in female dogs and predictors of peritonitis and prolonged postoperative hospitalization in surgically treated cases. BMC Vet Res. 2014;10:6.