Pyometra in Dogs and Cats: Early Signs After Heat, Open vs Closed Pyometra, Surgery Cost in India and Why Heat-Stopping Injections Are Risky

Quick answer: Pyometra is a pus-filled infection of the uterus that develops in unspayed female dogs (and sometimes cats), usually 2 to 8 weeks after a heat cycle. Watch for a dull dog that drinks and urinates much more than usual, stops eating, vomits, or has a smelly discharge from the vulva. It is an emergency. Without treatment the uterus can burst and toxins can shut down the kidneys. The cure is emergency spay surgery, and the only reliable prevention is spaying before problems start.

• Up to 1 in 4 unspayed female dogs develop pyometra by around 10 years of age.
• Most cases are in dogs over 5 years old, but it can happen after the first or second heat.
• In India, heat-stopping hormone injections and tablets are a major and avoidable cause.
• No discharge does not mean no pyometra. The closed type, with no discharge, is the most dangerous.

What is pyometra?

After every heat, a female dog’s body produces high levels of the hormone progesterone for about two months, whether or not she is pregnant. Progesterone thickens the lining of the uterus to prepare it for puppies, makes the uterine muscles relax, and lowers the local immune defence so sperm are not attacked.

Repeated heats without pregnancy gradually turn the uterine lining thick, cystic and glandular, a change called cystic endometrial hyperplasia. Bacteria from the dog’s own gut and skin, most commonly E. coli, travel up through the cervix while it is open during heat. In this thick, glandular, poorly defended uterus they multiply freely. Pus collects, and the uterus can swell to many times its normal size.

The danger is not only in the uterus. Bacterial toxins leak into the bloodstream, causing sepsis, kidney damage, low blood pressure and, if the uterine wall dies and ruptures, pus spills into the abdomen (peritonitis).

Open vs closed pyometra

Symptoms: what pet parents notice first

Early signs are vague and easy to blame on “weather”, “mood” or “after heat she is lazy”. Think of pyometra whenever an unspayed female who had a heat in the last two months becomes unwell.

• Drinking and urinating much more than usual: often the first sign; she empties her bowl, asks to go out at night, or has accidents
• Low energy, hiding, lying around
• Reduced or no appetite
• Vomiting, sometimes diarrhoea
• Vaginal discharge that is creamy, yellow, greenish, brown or blood-tinged, with a bad smell (open pyometra)
• Constant licking of the vulva
• Swollen or tight belly (closed pyometra)
• Fever early on; later a low temperature, cold paws and pale gums in shock
• Collapse, fast breathing, weak pulse: late-stage sepsis

Typical timeline after heat

Who is at risk?

• Unspayed female dogs over 5 years old, especially those who have never had puppies
• Dogs given heat-stopping injections or tablets: progesterone-type drugs such as medroxyprogesterone are still sold and injected in India to stop or delay heat; they strongly increase pyometra risk
• Dogs given oestrogen injections to “abort” a mating (mismating shots)
• Dogs whose heats are irregular or prolonged
• Breeds often reported at higher risk include Rottweilers, Golden Retrievers, Cocker Spaniels, German Shepherds, Labradors, Beagles and Pomeranians, but any breed and Indie dogs can be affected
• Unspayed female cats, less commonly than dogs

Stump pyometra: rarely, a spayed dog develops infection in a small piece of uterus left behind, usually because a bit of ovarian tissue also remained and she still shows heat signs.

Common myths that delay treatment

• “Let her have one litter first, it keeps her healthy.” There is no health benefit to one litter. Every heat without spaying adds risk of pyometra and breast tumours.
• “There is no discharge, so it cannot be pyometra.” Closed pyometra has no discharge and is the most dangerous kind.
• “Antibiotics from the chemist will cure it.” Antibiotics may reduce discharge for a few days while the infection keeps growing inside.
• “Injections to stop heat are safer than surgery.” Long-term hormone injections are one of the strongest risk factors for pyometra and breast cancer.
• “She is too old for surgery.” Age is not a disease. A planned spay in a healthy older dog is far safer than emergency surgery when she is septic.

How vets diagnose pyometra

1. History: date of last heat, any hormone injections, appetite, thirst, discharge.
2. Physical exam: temperature, hydration, gum colour, belly palpation, vulva and discharge.
3. Abdominal ultrasound: the most useful test; it shows an enlarged, fluid-filled uterus and helps tell pyometra from pregnancy.
4. X-ray: shows a large tube-shaped uterus; also used if pregnancy beyond about 45 days is possible.
5. Blood tests: white cell count (often very high, sometimes very low in severe sepsis), kidney values (urea, creatinine), liver enzymes, protein and electrolytes.
6. Vaginal cytology of any discharge, and sometimes culture.
7. Urinalysis: bacterial toxins often stop the kidneys concentrating urine, which explains the heavy thirst.

Treatment

Emergency spay (ovariohysterectomy): the treatment of choice

The infected uterus and both ovaries are removed. Before surgery the dog is stabilised with intravenous fluids, antibiotics and pain relief. The surgeon handles the enlarged, fragile uterus very carefully so it does not tear. If it has already ruptured, the abdomen is flushed repeatedly with warm sterile fluid. Most dogs stay in hospital for 1 to 3 days, longer if septic.

Surgery for pyometra is much more complex and risky than a routine spay, because the patient is sick and the uterus can weigh several kilograms. In India, costs commonly range from about ₹8,000 to ₹35,000 or more depending on city, dog size, how sick she is and hospital stay, compared with a fraction of that for a planned spay in a healthy young dog.

Medical treatment: only for selected breeding dogs

In a young, stable dog with open pyometra whose owners plan to breed her, vets may try hormone treatment (for example aglepristone and/or prostaglandins) with antibiotics to open the cervix and expel pus. It is not suitable for closed pyometra or sick dogs, takes days to weeks, causes side effects such as panting, vomiting and restlessness, and pyometra returns in many dogs. She should be bred on the next heat and spayed once breeding is finished.

Recovery at home after pyometra surgery

• Give every dose of antibiotics and pain medicine, usually for 10 to 14 days.
• Use a cone (E-collar) or surgical suit day and night until the stitches are removed.
• Lead walks only for toilet breaks for 10 to 14 days; no running, jumping, stairs or play.
• Check the wound twice a day. Mild pinkness is normal; swelling, gaping, pus or a bad smell is not.
• Offer small, bland meals for the first day or two, then her normal food.
• Thirst and appetite usually return to normal within a few days; ask your vet about a kidney recheck if she was very sick.

Most dogs treated in time recover fully, and after spaying pyometra cannot return, except the rare stump type.

Prevention

• Spay your female dog if you are not planning to breed her. Spaying before the first or second heat also greatly lowers the risk of breast tumours. Discuss timing with your vet, especially for large breeds.
• Avoid heat-stopping injections and tablets. If heat is difficult to manage, ask your vet about spaying instead.
• If you breed your dog, plan to spay her once breeding ends, ideally before 5 to 6 years of age.
• Note the dates of every heat. For two months afterwards, watch closely for thirst, appetite changes, discharge or dullness.

Read more in our dog heat cycle and pregnancy guide.

Pyometra in cats

Unspayed female cats can also develop pyometra, usually a few weeks after heat or after being mated. Cats often hide illness: watch for reduced appetite, vomiting, a swollen belly, discharge and excessive grooming of the rear end. Treatment is the same emergency spay.

Frequently asked questions

How long can a dog live with pyometra?

There is no safe waiting time. Some dogs with closed pyometra become critically ill within 24 to 48 hours of the first signs. See a vet the same day.

Can pyometra be treated with antibiotics alone?

No. Antibiotics are part of treatment, but alone they do not empty the infected uterus, and the infection usually comes back or worsens.

Can a dog get pyometra after one heat?

Yes, although it is less common. Risk increases with every heat cycle.

My dog has discharge after heat. Is it always pyometra?

No. A little clear or slightly bloody discharge can follow heat. But a creamy, yellow, brown or smelly discharge, especially with thirst, poor appetite or dullness, needs a vet check the same day.

Is pyometra contagious?

No. It is caused by the dog’s own bacteria and hormones and cannot spread to other dogs or people.

This article is for education and does not replace a veterinary examination. If your unspayed female dog or cat is unwell after a heat, see a vet immediately.

References

• Morrison BJ. Pyometra in Dogs. PetMD, 2023.
• Hagman R. Pyometra in small animals. Vet Clin North Am Small Anim Pract, 2018.
• Egenvall A, et al. Breed risk of pyometra in insured dogs in Sweden. J Vet Intern Med, 2001.
• Merck Veterinary Manual. Reproductive disorders of female dogs.