Is It Normal for My Dog to Have a Fever During Her Period?

When your dog enters her estrus or heat cycle, she'll probably show signs of agitation, and her scent will certainly excite male dogs in the area, but these are normal and healthy; fever should never be a part of it. It's not always easy to know when a dog has a fever. But, if she does and is experiencing vaginal bleeding along with other signs of illness, something's wrong and she needs to be checked out by a vet as soon as possible.

A common misconception is that if a dog's nose feels hot and dry to the touch, she's feverish. A dog's normal body temperature ranges between 101 and 102.5 degrees Fahrenheit, substantially higher than the normal human range of 97.6 to 99.6 degrees. The only way you or your vet can confirm fever is by inserting a special thermometer into your dog's rectum to take her internal body temperature. In the absence of such symptoms as lethargy, shivering, loss of appetite, vomiting, coughing and nasal discharge, fever is unlikely.

Vaginal bleeding is the most obvious sign of the onset of the estrus cycle in female dogs, but it should never be accompanied by fever. The age when a dog gets her first estrus or period varies with size and breed, but the VCA Animal Hospitals website says 6 months is average, although large and giant breeds can be as old as 2. During this two- to three-week cycle, which typically occurs twice a year, some dogs experience heavy bleeding, others not as much. At the outset, the discharge may appear thick and bloody but gradually changes to a paler, more watery-looking discharge.

Fever combined with bloody vaginal discharge can be signs of some extremely serious health conditions. The most common is pyometra, a bacterial uterine infection that can occur in unspayed dogs of any age but is most often seen in dogs over age 5. Typically, symptoms come on four to six weeks after the end of an estrus cycle. If the dog's cervix is open, a discharge consisting of blood and pus can alert the dog's owner that something's wrong. But if the cervix is closed, owners might not suspect a problem. Untreated, the infection can build up inside the pet until her uterus ruptures. Stump pyometra can occur in spayed dogs if any tissue from the ovaries, tubes or uterus was left behind during surgery. Since pyometra can quickly progress to septic shock and death, the condition is considered a medical emergency. The usual treatment involves surgical removal of the reproductive organs.

In dogs who have recently given birth to puppies, fever and bloody vaginal discharge can indicate metritis, a bacterial infection of the endometrium, the lining of the uterus. According to PetMD, other at-risk dogs include those who have had a medical abortion, have had a miscarriage or have been subjected to artificial insemination using nonsterile instruments. The bacteria most often involved are E. coli; once they establish themselves in the uterus, they can easily spread to the bloodstream, leading to fatal septic shock. Other warning signs include a swollen abdomen, dehydration, lethargy, reduced milk production and disinterest in caring for the litter. Treatment usually involves hospitalization, fluid replacement, antibiotic therapy and surgery.