Pyometra in unspayed female dogs (womb infection)

Recognise the signs

• Open pyometra — pus or bloody discharge from the vulva, often with a foul smell
• Closed pyometra — no discharge, but the dog becomes severely ill (more dangerous because of the missing warning sign)
• Drinking and urinating much more than usual
• Off food, vomiting, lethargy
• Distended belly (pus-filled womb)
• Pale gums, fast breathing, collapse in severe cases
• Often reaches the vet 2–8 weeks after the last season

First aid steps

1. Phone the vet immediately and describe the signs.
2. Note the date of the most recent season.
3. Do not give food or water if the dog is vomiting.
4. Carry the dog to the car if weak or collapsed.
5. Drive to the practice without delay.

While transporting to the vet

• Keep the dog warm and as comfortable as possible.
• Phone ahead — IV fluids, bloods, ultrasound, and surgery may be prepared.
• Bring a record of recent seasons, weight, and any current medications.

Common causes

• Unspayed female dogs, typically 4–8 weeks after a season
• Hormonal changes during the dioestrus phase create conditions for bacterial infection
• Risk increases with age — most cases over 6 years
• Mismating injections and some progesterone treatments raise risk

What the vet will need to know

• Spay status (always confirm)
• Date of most recent season
• Any vaginal discharge — colour, smell, amount
• Drinking and urinating volume changes
• Appetite and energy
• Any recent hormone treatments or mismating injection

Aftercare

• Surgical removal of the uterus and ovaries (ovariohysterectomy) is the standard of care — essentially an emergency spay on a sick dog.
• Hospitalisation typically 2–5 days with IV fluids and antibiotics.
• Recovery at home: rest, buster collar, short lead walks for 10–14 days.
• Most dogs recover well; outcomes are far better with prompt surgery.

Prevention

• Spaying is the only fully effective prevention — almost eliminates pyometra risk.
• Discuss timing of spay with the vet for individual dogs (not all breeds benefit from the same timing).
• Avoid hormone treatments where possible.
• If keeping a bitch entire for breeding, owners need to know the warning signs and have a clear plan for retirement and spay.

Breed-specific notes

• Higher pyometra incidence: Bernese Mountain Dog, Rottweiler, Rough Collie, Cavalier King Charles Spaniel, Golden Retriever, Leonberger, English Bulldog.
• Risk rises with age in all breeds.

Frequently asked questions

Related topics

• Dog vomiting — when to worry
• Dog drinking more water than usual (polydipsia)
• Recognising and managing shock in dogs and cats