Bacterial Infection (Metritis) of the Uterus in Dogs

PetMD Editorial
By PetMD Editorial on Sep. 19, 2008
Bacterial Infection (Metritis) of the Uterus in Dogs

Metritis in Dogs

Metritis is inflammation of the endometrium (lining) of the uterus due to a bacterial infection, usually occurring within a week after a dog has given birth. It can also develop after a natural or medical abortion, miscarriage, or after a non-sterile artificial insemination. The bacteria that are most often responsible for infection of the uterus are gram-negative bacteria like Escherichia coli, which often spreads into the blood, causing a blood infection. The infection may lead to sterility, and if left untreated, septic shock, a lethal condition, may follow.

Symptoms and Types

  • Discharge from the vulva that smells bad; discharge with pus, or pus mixed with blood; discharge that is dark green
  • Swollen, dough-like abdomen
  • Dehydration (the skin stays tented for a few seconds when pinched)
  • Dark red gums
  • Fever
  • Reduced milk production
  • Depression
  • Lack of appetite
  • Neglect of puppies
  • Increased heart rate if the bacterial infection has become systemic


  • Difficult birth
  • Prolonged delivery, perhaps with a large litter
  • Obstetric manipulation
  • Retained fetuses or placentas
  • Natural or medical abortion, miscarriage
  • Natural or artificial insemination (rare)


Your veterinarian will perform a thorough physical exam, including a chemical blood profile, a complete blood count, an electrolyte panel, and a urinalysis. These tests will help your veterinarian to determine whether the bacterial infection has spread to the bloodstream, where the infection might have originated, and how dehydrated your dog is. You will need to give a thorough history of your dog's health, onset of symptoms, and possible incidents that might have precipitated this condition.

Diagnostic tools, like radiograph and ultrasound imaging, will allow your veterinarian to visually examine the interior of the uterus for any retained fetuses, excess fluid accumulation, and/or abnormal amounts of abdominal fluid production due to uterine rupture.

A sample of the vaginal discharge will also be taken for cytologic (microscopic) examination. A culture of both aerobic and anaerobic bacteria (bacteria that lives with oxygen, or without oxygen, respectively) will be used for identifying the bacterial populations present in the blood, and a sensitivity of the isolated bacteria will be performed so that the most appropriate antibiotic treatments can be prescribed.


Your dog will need to be hospitalized for fluid therapy, and to correct and stabilize any electrolyte imbalances. If the infection has reached sepsis, your dog will also be treated for shock. Your dog will also need to be placed on broad-spectrum antibiotics until the bacterial culture and sensitivity results return from the lab; then, depending on the results of the tests, your veterinarian will switch your dog to the antibiotic best suited for eliminating the bacteria that are causing the infection.

If the metritis is not in an advanced stage, your dog will most likely respond to medical treatment. However, medical treatment does not always prevent the infection from progressing to a generalized abdominal infection and ruptured uterus. If future breeding is not planned, having your dog spayed is the treatment of choice. This solution is especially appropriate when retained fetuses or placentas are present within the uterus, when the uterus has ruptured, or when the uterus is severely infected. Patients suffering from a long-term infection that is not responding to medical treatment may improve after a surgical cleansing of the uterus.

Living and Management

If your dog is nursing and has been diagnosed with a bacterial blood infection, it will be better to hand-raise her puppies to prevent transmission of the infection through her milk, and to prevent exposure to the possibly harmful effects of antibiotics on the puppies undeveloped systems. Keep in mind that animals that have been treated for infection have a chance of becoming less fertile or infertile, making future breeding difficult, or even impossible. 

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