Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Pyometra in Cats: Our Vet Explains the Signs, Causes, Treatments & FAQ

a siamese cat getting examined by a vet at the clinic

Pyometra in cats is a serious infection where your cat’s uterus fills with pus. Your cat can become very ill, and it can even be fatal.

It is thought to be caused by hormonal changes affecting the lining of the uterus and the presence of bacteria. The most effective treatment method is to perform surgery to remove the infected uterus. There are other options available if the cat is intended for breeding, but these are not as reliable. If prompt diagnosis and administration of treatment are given, prognosis is usually good.

If the infection is left, it has the potential to spread into the bloodstream and cause sepsis which is often fatal.

divider 3 paws

What Is Pyometra in Cats?

Pyometra is a serious and life-threatening infection that occurs in the uterus of cats. In Latin, “pyo” means pus, and “metra” means uterus, so it translates as pus in the uterus. In this condition, the uterus fills with pus produced by bacteria. A pyometra in cats can be open or closed. Open infections involve vaginal discharge leaking out—there is no discharge seen in closed infections. This can be even more dangerous as it can be more difficult to detect. Cats become very sick with a high temperature, reduced appetite, lethargy, and vomiting amongst other things. Treatment can involve antibiotics or surgical removal of the uterus and ovaries. This surgery is called an ovariohysterectomy.

Any cat that has not been neutered can develop a pyometra. It is more commonly seen in older cats that have had lots of heat cycles without being mated. Pyometra usually occurs when a cat has been in heat in the last month.

Being in “heat” is the term used to describe the period when your cat is ready to mate and produce kittens. After the heat cycle finishes, there is a big shift in the circulating hormones which makes it easier for bacteria to establish an infection in the uterus. Most cats have a good prognosis if the problem is identified promptly and they receive treatment straight away. If left untreated, pyometra can have fatal consequences. Pyometra is a medical emergency and if you are suspicious your cat may have a pyometra, you need to go to a vet immediately. Prevention of pyometra is easily done by spaying cats.

Photo Credit Lee Charlie, Shutterstock

What Are the Signs of Pyometra in Cats?

Clinical signs displayed by a cat with pyometra firstly depend on whether the cat’s cervix (the entrance to the uterus) is open or closed. Signs are often more obvious when the cervix is open as owners will see discharge leaking out of the vagina, however, a closed infection can be more serious as the infection is trapped inside the body and has no route of exit.

Typical signs of pyometra in the cat include:
  • Creamy or blood-tinged vaginal discharge
  • Reduced appetite
  • Lethargic
  • Increased water intake
  • Increased urination
  • Pain reaction when touched on the back or stomach
  • Fever
  • Vomiting
  • Diarrhea
  • Pale gums
  • Weakness
  • Collapse

Consulting a veterinarian is recommended for the best course of action.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

What Are the Causes of Pyometra in Cats?

The initial cause of pyometra is hormonal changes making the uterus more susceptible to infections. It usually occurs in older female cats that have not been neutered and have never had kittens. This happens because when a cat is in heat, they experience hormonal changes that cause the uterine walls to thicken in preparation for pregnancy. If the uterus wall repeatedly thickens with no implantation of a pregnancy, cysts develop.

When these cysts burst, they release fluid that facilitates the growth of bacteria. While the cat is in heat, her cervix is open to allow for sperm to swim into the vagina if she is mated. Usually, the white blood cells of the cat’s immune system are stopped from entering the uterus while the cat is in heat. This is to allow the sperm to enter without being identified and destroyed by the white blood cells, however, it also prevents them from acting against bacteria. This means bacteria can enter the uterus and multiply rapidly. As the bacteria grow, the pus is released and a pyometra occurs. When the uterus is full of bacteria and pus, there are toxins released. These toxins can enter the bloodstream and cause sepsis.

The bacteria usually involved in pyometra is E. Coli. This bacterium is spread from the vagina into the uterus. This is facilitated by the cervix being open and soft during the heat cycle. A combination of these different things means the chances of infection are high at this time.

Some cats may develop something called a stump pyometra This occurs when an infection develops in the stump of tissue that has been left behind after a neutering procedure. When a cat is spayed, the reproductive tract is removed from the ovaries to the uterus. The infection develops in the small piece of tissue left behind once the surgery has been completed. This is extremely uncommon in cats.

cat in heat
Photo Credit: Faroe, Shutterstock

Diagnosis of Pyometra in Cats

A vet will take a detailed history from you and perform a thorough clinical exam. They will need to know if your cat has been neutered and if they have been mated recently (if this information is known by the owner).

All un-neutered females showing any of the clinical signs above should be investigated for having a pyometra as it can be difficult to spot if a closed infection is present. Diagnostic tests that a vet may perform include routine blood tests, urinalysis, X-rays of the abdomen, and an ultrasound scan of the abdomen. The vet may take a sample of any vaginal discharge present to be examined.

How Do I Care for a Cat with Pyometra?

The most common treatment for pyometra is surgical removal of the whole uterus and the ovaries too. This removes the source of the infection completely. On some occasions, other treatment options can be offered as well as surgery. These options have a lower success rate than surgery and more risks are involved. It is usually owners of breeding cats that will ask for these as they want to breed from their cat in the future.

One option is the use of antibiotics to fight the bacteria. Another option is using prostaglandins. These are hormones that cause uterine contractions and open up the cervix. This helps expel some of the pus in the uterus. These two options are often used in conjunction with each other.

Other management such as supportive treatment like intravenous fluid therapy will also be used.

divider 3 paws

Frequently Asked Questions

What happens if pyometra is left untreated?

If the pyometra infection is left untreated, it is likely your cat will become very sick. The chances of the infection resolving on its own are slim. The bacteria can produce toxins and the toxins can travel from the uterus into the bloodstream, this causes toxic shock syndrome and can be fatal. If the cat does not receive any treatment in the case of a closed pyometra, the uterus can rupture causing septic peritonitis where the abdomen is filled with pus. This is almost always fatal.

sad-cat-with-green-eyes-lies-at-home
Image Credit: Julia Cherk, Shutterstock

Can pyometra in cats be prevented?

It is possible to prevent the occurrence of pyometra infection by spaying your cat before the infection has developed. An ovariohysterectomy is recommended as this involves the removal of both the ovaries and the uterus. If the owner wants to breed their cat, they should be bred at an appropriate age to minimize the risk of pyometra developing.

How long can a cat live with pyometra?

Once the infection has become established, if the cat does not receive prompt treatment, the cat will deteriorate very quickly. It doesn’t take much time for pyometra to kill a cat. The infection can be fatal within a few days. Closed pyometra infections will generally be more severe and affect the cat quickly as the pus is trapped inside the uterus and has no way to be expelled.

divider 3 paws

Conclusion

Pyometra in cats is a potentially fatal condition that occurs when a bacterial infection becomes established in your cat’s uterus. It is usually seen in unspayed middle-aged or older female cats. The gold standard of treatment is an ovariohysterectomy to remove the ovaries and uterus.

This usually has a positive outcome if it is carried out promptly. It is a medical emergency and if you suspect your cat has pyometra, you must go to a vet immediately.


Featured Photo Credit: Sergey Nivens, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Egyptian Mau Cat Breed: Info, Pictures, Temperament & More

You’ll notice the Egyptian Mau right away because of their stunning silvery coats and gorgeous eyes. You might wonder just what this cat...

Are Marigolds Poisonous to Cats? Vet-Reviewed Houseplants Examined

If you are looking to grow this beautiful plant in your house with your feline companion or your kitty has taken a nibble...

Cat Sprayed by Skunk? Our Vet Explains What To Do

If your cat has returned home feeling sorry for themselves and wearing that distinctive odor, “Eau de Skunk”, there are some important things...

Can Cats Carry Bed Bugs? Vet-Reviewed Info, Risks & What to Do

Bed bugs are a major public health problem. Many people associate them with the filthiest, most run-down apartments, but the truth is that...

More related

CatGenie Litter Box vs. Litter-Robot: 2025 Comparison

Scooping poop and emptying the litter box is so last year! Our homes are more connected than ever before, so it makes sense...

Why Do Seemingly Healthy Old Cats Suddenly Get Sick & Die? 5 Possible Reasons (Vet Answer)

One of the hardest parts of owning a pet is the inevitable end when we have to say goodbye. In many cases, we...

Why Do Cats Sleep So Much? 6 Vet-Approved Reasons

Chances are that while you’re reading this article, it’s probably quite likely that your cat(s) are sleeping: on your lap, in the sink,...

Sudden Blindness in Cats: 4 Vet Approved Possible Causes and What to Do

Cats are known for having great peripheral and night vision. They spot things like mice and flies much easier than we humans can....

Keep reading

Are Raid Fly Ribbons Poisonous to Cats? Vet Approved Facts & FAQ

It can be tricky to care for our pets while attempting to get rid of pests. If you have many bugs intruding on your home, finding the right way to repel or kill them without endangering your cats can be...

flies caught in a flycatcher tape

7 Best Kitten Foods for Diarrhea in 2025 – Reviews & Top Picks

If you have a kitten with diarrhea, it can be a scary experience. Diarrhea can dehydrate your kitten and rob it of important nutrients it needs to grow into a healthy cat. In some cases, you can improve the situation...

American cat kittens eating

Can You Wash a Cat With Just Water? 6 Vet-Reviewed Tips & FAQs

While it’s true that cats spend an excessive amount of time grooming, occasionally, your cat might get into something that their tongue won’t be able to handle. For example, a senior cat may not be able to clean themselves as...

sphynx cat taking a bath in the kitchen sink

Can You Spay a Cat in Heat? Risks & Precautions

Most veterinarians generally recommend that a kitten be spayed before her first heat. But that can get tricky since kittens don’t go into heat on anyone’s schedules except their own. For this reason, most shelters will do what’s called a...

cat neutered

Is It True That All Cats Chirp? 5 Reasons Why They Do It

Cats use various vocalizations to communicate with us, and one of these vocalizations is the cute chirping sound you become accustomed to hearing when your cat is obsessed with a bird or bug on the other side of the window....

white cat chirping

What Are Cat Paws Made Of? 5 Vet-Reviewed Facts & FAQ

Cats’ paws are incredible and are used for a host of different things. Paws help with balance and carrying the load of the cat, and they also provide protection, offer grip, and even dissipate energy, which is how cats can...

close up paws of orange cat

Can Cats Eat Bird Seed? Vet-Approved Nutritional Facts & Warnings

If you have a cat that stays indoors, you likely won’t ever have to worry about him eating bird seed. But if your cat spends lots of time outdoors, you’ve probably noticed him eating bird seed that has fallen on...

Can Cats Eat Bird Seed

15 Hazards That Could Hurt or Kill Your Cat & How to Avoid Them (Vet Reviewed)

When you are at home relaxing with your cat, you might be totally oblivious to all the hazards around the home. After all, we don’t foresee some events, making it difficult to navigate. While we could go on for hours...

vet wrapping cat's injured paw with bandage