Pyometra is a serious and life-threatening infection of the womb (uterus). It happens when the womb fills with pus, making dogs extremely unwell. Without fast treatment, pyometra can lead to dehydration, kidney failure, blood poisoning (sepsis) and, sadly, can be fatal.
Once a pyometra has developed, the most effective treatment is usually emergency surgery to remove the infected womb. This is why pyometra is always treated as an emergency.
Pyometra is most commonly seen in older, unspayed female dogs, but it can at any age.
Pyometra is usually caused by a bacterial infection, most often E. coli. The condition tends to develop four to eight weeks after a season (heat).
During a season, hormonal changes cause the lining of the womb to thicken and suppress the immune system slightly. While this is a normal part of the reproductive cycle, it also creates the perfect environment for bacteria to grow. If bacteria enter the womb at this time, a serious infection can develop.
There are two types of pyometra:
Open pyometra – the cervix is open, allowing pus or discharge to drain from the vulva. This can make the condition easier to spot.
Closed pyometra – the cervix is closed, trapping pus inside the womb. This form is particularly dangerous, as pressure can build up and the womb may rupture.
Early symptoms can be subtle and are sometimes mistaken for normal ageing or mild illness. As the infection progresses, dogs often become very unwell.
Common signs include:
If you notice any of these signs, especially in an unspayed female dog who has recently been in season, contact your vet immediately. Acting quickly can save your dog’s life.
Your vet will ask about your dog’s recent seasons and any changes in her behaviour, appetite or thirst. They will examine her abdomen and may perform an ultrasound scan to look at the womb.
Blood and urine tests are often carried out to assess how badly your dog is affected and to check organ function.
Most dogs with pyometra need urgent surgery to remove the infected womb. While this operation is similar to a routine spay, it carries a higher risk because the womb is enlarged, fragile and full of infection.
The earlier surgery is performed, the better the chances of survival. Delays increase the risk of complications, including the womb rupturing and infection spreading through the body.
Alongside surgery, dogs usually need:
Some dogs will need to stay in the clinic for a day or two after surgery. Once home, careful nursing is essential.
This usually includes:
Always contact your vet if you’re worried about your dog’s recovery.
The outlook for dogs with pyometra depends on how quickly treatment begins and how unwell they are at the time of diagnosis. Many dogs recover well if treated promptly, but the risks are higher in older dogs or those who are already very sick.
Sadly, pyometra can be fatal if treatment is delayed.
Yes. Spaying completely prevents pyometra and is the most effective way to protect your dog from this condition.
While most spayed dogs cannot develop pyometra, a very rare condition called stump pyometra can occur if a small piece of womb tissue remains after surgery.
Pyometra is always an emergency.
Contact your vet immediately if your dog:
You know your dog best, if something doesn’t seem right, it’s always safest to seek veterinary advice.
