Canine Pyometra : a Real Danger for Reproductive Females

Canine Pyometra

Guest Writer: Franklin Medina

If you have reproductively intact dogs, and have been contemplating breeding, you have probably had any number of well-meaning people tell you that it’s a bad idea. They point to the increased nutritional needs of the bitch, problems that can occur during whelping, the inconvenience of having to take time off work to be at home with the bitch when she whelps, and so on. Most, though, won’t think to mention a serious health issue that sometimes can occur if the bitch experiences heats without being bred – it’s canine pyometra, and it can be deadly.

What is Canine Pyometra?

Pyometra is an infection that can result from hormonal changes that work during heat to prevent white blood cells from entering the bitch’s uterus. If the white blood cells were not suppressed during the heat, the bitch’s immune system would either damage or kill the male’s sperm, and breeding would not be successful.

The problem here is that even if the bitch is not bred, the levels of the hormone progesterone will still be elevated for up to two months, thickening the uterine lining in preparation for a pregnancy that is not going to happen. With every heat that does not result in a breeding, the uterine lining will continue to thicken. Cysts can form and leak fluids that provide a perfect breeding ground for bacteria. The high progesterone level also decreases the ability of the uterine walls to contract in order to expel the bacteria-laden fluid. Then, infection can occur.

How Do the Bacteria Enter the Uterus?

When the bitch is in heat, the cervix relaxes in order to facilitate the entry of sperm. Unfortunately, this means that bacteria can also enter easily. The bacteria that typically occupy only the vagina then work their way up into the uterus.

Can Any Intact Female Develop Pyometra?

Yes. However, it is more common among older dogs, again because of the repeated heats that cause uterine thickening without fertilization. When canine pyometra develops, it is generally within 2-8 weeks following the heat, and, in fact, it will often look like a prolonged heat – the dog continues to drip blood after the heat should have passed.

What Other Signs Could Indicate Pyometra?

If the bitch’s cervix remains open, you may notice pus in the area of the vagina, under her tail, or on furniture or bedding that she has used. She may also be reluctant to eat, have a fever, or appear to be depressed.

If the cervix, closes, you will not see pus, because there will be no way for it to drain. This is the worst case scenario. The pus will remain in the uterus, and toxins will be absorbed into her bloodstream. She will develop a distended abdomen and become very listless. She may also develop diarrhea, and may vomit.

The toxins that are delivered by the bacteria can also affect the kidneys, and the bitch may drink a great deal of water and urinate copiously. This is true of both open-cervix and closed-cervix pyometra.

Diagnosing Canine Pyometra

In the early stages, a bitch with pyometra may only have a bit of vaginal discharge, and appear otherwise healthy. Most of the time, though, owners do not suspect that there could be a serious problem until the illness has progressed.

If your veterinarian suspects pyometra, he or she will take a blood sample, and examine it for an elevated white blood cell count and elevated globulins. Globulins are proteins that that are associated with the dog’s immune system. If you are able to get a urine sample, the veterinarian will examine it as well, since concentrated urine can indicate toxicity (associated with the harmful bacteria) affecting the kidneys.

If the dog’s cervix is closed, the veterinarian will take an abdominal x-ray to determine if the uterus is enlarged. If the cervix is open, x-rays will not be done, as the uterus can be presumed not to be overly enlarged, and any results will be inconclusive. An ultrasound may also be done to check for enlargement of the uterus, thickening of the uterine walls, and fluid accumulation.

Treating Pyometra

The best treatment is to have the dog spayed. At this point, though, spaying is not the routine operation that it normally is. The dog will probably already be very ill, the surgery will be complicated, and the post-surgical hospitalization will be longer. The dog will be given fluids intravenously in order to stabilize her before and after the operation. She will also be given a course of antibiotics, usually for a couple of weeks following the surgery.

Canine Pyometra, a serious danger to breeding female dogs.

Image: Morten Skovgaard, Flickr

What if I Have a Valuable Breeding Bitch – Are There Other Treatments?

Your dog could be treated using prostaglandins. These are hormones that work to first of all reduce the level of progesterone in the blood, and then to open the cervix and encourage the uterus to contract and flush out pus and bacteria. However, this treatment is not always successful, and there can be side effects like panting, restlessness, vomiting, drooling and abdominal discomfort.

Also, because prostaglandins work to encourage uterine contractions, the uterus could actually rupture. Then, infection will pour out into the dog’s abdominal cavity, and peritonitis will result. This is a very real danger, especially in cases of closed-cervix pyometra.

With this treatment, too, you have a window of about 48 hours to see improvement. If there is none, then your dog is going to need surgery to save her life – and she will be very ill, and not a good candidate for surgery.

Some Statistics for You to Think About

If you should happen to be vacillating between spaying and non-surgical treatment, consider the following:

  • If you elect to go with prostaglandin therapy for your dog, and she has open-cervix pyometra, there is a 10-25% chance that the treatment will not be successful.
  • With closed-cervix pyometra, there is a 60-75% chance that the treatment will not be successful.
  • With both types of pyometra, the chances that the condition will recur is 50-75%.
  • You will have only a 25-50% chance of ever having a successful breeding later on.

These are sobering statistics. I know what I would do if one of my dogs developed pyometra – I would have her spayed immediately, because I value her more as a friend and beloved companion than I do as a puppy factory.


Canine pyometra is a very serious medical condition, and, if not promptly treated, the chances of the dog recovering are slim to none. If you have an intact female and allow her to go through successive heats without being bred, pyometra is a very real possibility. Watch her closely, and at the merest suspicion of pyometra, see your veterinarian immediately. Your dog’s life could depend on how quickly you get help.


Guest Author: Franklin Medina owns and breeds Boxers. You can read more from Franklin at Simply For Dogs


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Animal Bliss - A really cool blog about Animals - domestic pets and wildlife too.


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