Do Dogs Have Periods? (Mystery Solved)

We usually don’t pay much mind to a female dog’s reproductive system unless she’s pregnant. Yet we obviously know that female dogs carry pups in her belly and give birth to live offspring. This begs a rather important question if you own a non-neutered female: Do dogs have periods?

Dogs Don’t Have Periods Like Humans Have Periods

Even though dogs have similar reproductive organs as other mammals including humans, dogs do not have periods in the same manner that female humans have periods. The main difference here is that dogs do not go through a 28-day menstrual cycle like human women. Rather, they go through what is known as an estrous cycle.

An estrous cycle in female dogs will last about 180 days and will typically first occur anywhere from 5 to 14 months depending on the size of the breed. At the end of this cycle, a dog will come into heat. When she is in this condition, which typically lasts from 2 to 3 weeks, she will experience some unique physiological changes and identifiers, including some that may lead owners to believe she is menstruating like a human would.

For instance, her body will prepare itself for the carrying of offspring, which includes a fluctuation in estrogen levels, the swelling of the vulva, and vaginal discharge. This color of this discharge will range from reddish-brown to light pink, depending on what part of the heat cycle the dog is experiencing. The discharge amount can be heavy, or it could be barely noticeable - it depends on the breed of dog.

Isn’t This Discharge a Sign of Menstruation?

The presence of a dog's bloody discharge may be initially interpreted as a period by pet owners. While blood is present in the discharge, this secretion is different than the blood that is secreted by human females during the menstrual cycle. It also serves a different purpose.

Unlike menstruation, where the blood originates from the uterus, the blood that is part of a dog’s heat cycle is strictly produced by the vagina. This blood is also not part of any secretion mechanism; rather, it is used as a signal for the beginning of fertility. There is nutrient-rich blood that is produced by a dog’s reproductive system during the cycle, but that gets absorbed back into a dog’s body once an egg goes unfertilized as opposed to being flushed out of the body.

Other Signs to Be Mindful of During the Estrous Cycle

Remember, your dog will want to mate when she’s in the throes of the heat cycle. As such, you can expect to see some rather unusual behavior from her during this time. Some of these behaviors may appear that she’s taken a step back in the training department.

For instance, your dog may urinate with greater frequency while she’s in heat. She may also develop a habit of “marking” spots and objects around the house with urine. This is because her pee carries hormones and pheromones that naturally signal male dogs that she is in her reproductive state.

You may also find her acting a little less lady-like if you get her around male dogs. For instance, she may engage in some aggressive, playful behaviors, such as using her nose to poke the male. She may also chuck subtlety right out the window and shove her rear into a male dog’s chest with her tail pushed to one side.

The Importance of Spaying

If you think that this cycle will gradually stop with your dog, think again. Another important difference between dogs and humans is that dogs do not go into menopause during their life. Even though the estrous cycle is designed in such a way that they will only be in heat about twice a year on average, their reproductive system is designed to work well into their senior years.

Because of this, it is imperative that you spay your dog if you have no plans on breeding. It is perfectly safe to spay a dog as early as six to eight weeks, and doing so will benefit your dog's long-term health, as she will be less susceptible to certain cancers and other diseases. It is really one of the best things you can do for your dog in the long run.