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

Does Catnip Help Cats With Pain? Our Vet Answers & Explains

No cat owner likes to see their cat in pain, and they will often go to great lengths to keep them healthy and...

How Much Do Turkish Angora Cost In 2025? Complete Price Guide

The Turkish Angora is one of the sweetest and most beautiful breeds in the cat world. These playful, affectionate cats are a favorite...

Cat Sitter Checklist: Vet-Verified Crucial Info You Should Leave With Your Sitter

There will inevitably come a time in your tenure as a cat owner when you’ll need to leave your beloved fur baby behind...

Ask Dr. Paola – Low Iron, Newborns & Digestive Issues (September 29, 2025)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

More related

Telepathic Communication With Your Cat: How Olga Anticipates My Actions

Hi, I’m Christopher! Read my introduction to learn more about me and my silly Russian Blue cat, Olga. Cats have a reputation for...

Will Your Cat Miss You If You Give Them Away? Cat Emotions Explained

Cats are loyal, loving animals that can form strong bonds with their owners. But what happens when you give your cat away? Is...

Cat Poop Chart: Colors, Consistency & More (Vet-Reviewed)

We all know cleaning the litter box is an unpleasant but crucial part of pet ownership. You don’t want to spend more time...

Can You Use Horse Pellets for Cat Litter? Vet-Approved Facts & Tips

If you are a cat owner, you know that you need various supplies to properly care for your feline, including litter. Nowadays, there...

Keep reading

Nutro Cat Food Review of 2025: Recalls, Pros & Cons

Nutro Cat Food Review Summary Founded in the 1920s, Nutro is an American pet food manufacturing company and a subsidiary of Mars Inc., which also manufactures other pet food brands, including Whiskas, Royal Canin, and Iams, and is now headquartered...

Nutro Cat Food Review

Can Cats Eat Meatloaf? Vet-Reviewed Diet Facts & FAQ

Whenever you sit down to eat, you can be sure you’ll have the full attention of your cat. While we might know better than to share all our food with them, our kitty’s twitching nose and unrelenting stare can make...

Can Cats Eat Meatloaf

Are Cast Iron Plants Toxic To Cats? Vet-Reviewed Houseplants Examined

If you have a green thumb and a cat obsession, you know that your two great loves don’t always coexist seamlessly. Not all flowers and plants are safe for cats, so caution is required any time you add to your...

Catster_Are Cast Iron Plants Toxic to Cats

Do Cats Need Professional Groomers? Vet-Reviewed Cleaning Facts & Tips

Grooming is a must for all cats, long-haired and short-haired alike, but do cats need to be professionally groomed? Not necessarily. You can groom your cat at home instead of splashing out on professional grooming, but there are some instances...

professional groomer grooming persian cat

5 Best Litter for Cats with Asthma in 2025 – Reviews & Top Picks

It can be tough to parent a cat with asthma, particularly because of cat litter. The tiny particles and dust that get kicked up when a cat litter box is being cleaned can really affect asthma-suffering cats. Many people therefore...

kitten in the litter box

Can Cats Eat Sardines? Health Benefits & FAQ

Does your cat come running after the sound of a cracking can of sardines? Most felines are attracted to these tiny fish and will likely commit the sound of an opening can to memory. As you try to enjoy your...

Can Cats Eat Sardines

Why Is My Cat’s Nose Wet? Vet-Approved Answer

If you live in the Northern Hemisphere, the winter months bring with them cold and flu season. Red, runny noses plague humans during this time, but what does it mean when a cat has a cold, wet nose? If you’re...

nose and mouth and whisker of a cat close-up

Why Do My Cat’s Farts Smell Like Eggs? Our Vet Explains

Have you ever noticed that your cat’s farts smell like rotten eggs? Is there a way to prevent this unpleasant scent? That rotten egg odor is primarily due to sulfur compounds produced in the digestive process. When cats eat certain...

Cat Stinky