Pyometra is a potentially life-threatening condition for female dogs.
Technically, it’s a disease of the unaltered female dog — a serious infection of the uterus. It usually affects older unspayed dogs.

Unfortunately, it’s a condition that most pet owners know nothing about. I didn’t know about it myself until recently.
So, in order to help you understand what pyometra is, how it happens, and how to prevent it from happening to your dog, I thought I’d share this info for all of my friends that have female dogs.
What Is Pyometra?
Since it involves the dog’s uterus, it’s first necessary to understand the breeding cycle of a female dog.
After the age of 6 months or so, most female dogs experience an estrous cycle (“go into heat”) 2 to 3 times per year.
Most dogs come into heat twice per year, or about every 6 months, although the interval can vary between breeds, and from dog to dog. Small breed dogs may cycle 3 times per year, while giant breed dogs may only cycle once every 12-18 months.
During the estrous cycle, hormonal fluctuations cause changes to occur in the dog’s body:
- The uterine lining thickens.
- The entrance to the uterus (the cervix) opens.
- In the latter stages of a typical canine estrous cycle, the dog’s body produces a hormone called progesterone.
Progesterone is necessary for the healthy gestation of puppies. But in some female dogs, an adverse reaction to the hormone progesterone causes infection to grow and thrive in the dog’s uterus.
The bacteria enter the uterus through the normally closed cervix.
If left unchecked, these bacteria can grow into the serious and life-threatening infection called pyometra and remember that when you adopt a dog, you will need to invest in dog training so that your new pet will become a wonderful part of the family, specially if your dog suffer from any condition.
Types Of Pyometra In Dogs
Pyometra usually occurs within 2 to 8 weeks after the last estrus or “heat cycle”.
There are 2 types of pyometra:
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- Open pyometra – happens while the cervix is still open
- Closed pyometra – happens after the cervix has closed and is much more dangerous and difficult to treat
With open pyometra, you may observe pus being discharged from your dog’s vulva. Lethargy, excessive thirst, abdominal pain, bloating or swelling, and excessive licking of the vaginal opening are also symptoms of pyometra. If your dog is female, unspayed, and exhibits any of the symptoms listed above, call your veterinarian immediately.
Read more: A Warning To Anyone With An Unspayed Female Dog: Here’s What You Need To Know About Pyometra In Dogs
