Do dogs have periods? No—at least not like humans do. Dogs do not menstruate and are only receptive to mating when actively in heat. Do dogs go through menopause? No; dogs can become pregnant throughout their entire lives.
There’s no short answer to explain the reproductive cycle of a female dog, especially in comparison to the human menstrual cycle. Here’s a guide to help you better understand dog heat cycles and all the changes that come with them.
When Do Dogs Go Into Heat?
The term “time of the month” in relation to our canine companions is a misnomer. Female dogs do not cycle every month, but usually only once or twice a year. The average is about every seven months.
Just as the duration of a human menstrual cycle varies from person to person, every dog is different, and there can be variations among breeds and even variations from one cycle to another in the same animal.
Phases of Dog Heat Cycles
A female dog’s reproductive cycle is called an estrous cycle and is broken down into three different phases:
- Proestrus is the beginning of the heat cycle. It’s characterized by swelling of the vulva and a blood-tinged vaginal discharge. Female dogs will not allow mating to occur in this phase. This phase can last anywhere from a few days to four weeks. On average, it lasts 7-10 days.
- Estrus is also known as “heat.” This is the time when the female dog will allow mating to occur. This phase of the cycle lasts anywhere from 3-21 days, with an average length of 9 days.
- Anestrus is defined as the timeframe when cycling ceases. This phase usually lasts about four to five months.
How Do Male Dogs Know a Female Dog Is in Heat?
When a female dog is in heat, her vaginal and urinary secretions will contain different pheromones than when she is not in heat. Male dogs’ keen sense of smell can detect these pheromones.
What Happens When a Dog Goes Into Heat? How Can You Tell Your Dog Is in Heat?
Dog pheromones are undetectable to humans, but there are several other reliable ways to tell if your dog’s in heat, including:
- Physical changes: You may notice continued swelling of the vulva, cessation of the bloody discharge, or even a change in the color (usually straw-like). Your dog may also arch her back when pressure is applied to her lower back, and you may notice her moving her tail sideways.
- Behavioral changes: Courtship-like behavior is often initiated by the female dog and may include releasing pheromones, vocalization, postural changes, increased physical activity, urinating in the presence of a male dog, or allowing male interest (e.g., sniffing or licking the vulva).
- Diagnostic testing: Vaginal cytology (similar to a pap smear) is a low-cost, relatively quick and valuable monitoring tool that can be performed on an outpatient basis with the veterinarian.
When in doubt, consult your veterinarian.
At What Age Do Dogs Go Into Heat?
The first time you may notice that your dog has come into heat may be as soon as 6 months of age or as late as 24 months of age. Even though dogs can become pregnant during this timeframe, it’s generally not advisable, as they are still not fully mature.
Do Dogs Go Through Menopause?
In short, dogs do not go through menopause. Because their reproductive cycles are different than in humans, dogs can continue to go into heat and subsequently become pregnant throughout their lives.
You may notice, however, that your dog’s cycle may occur less often, or the duration seems longer from one heat to the next. That’s normal in dogs as they age; however, dogs that have ceased having cycles altogether should be examined by a veterinarian, as this can signal an underlying health condition or metabolic disease process.
But just because dogs can get pregnant as seniors doesn’t mean they should. Litters tend to be smaller, there may be more puppy deaths, and labor may be more difficult if carried to term. Moreover, females that get pregnant after 8 years of age are more at risk of developing pyometra, which is a life-threatening disease.
Having Dogs Spayed Is the Most Reliable Form of Dog Birth Control
Preventing your dog from getting pregnant is not as easy as it sounds. Don’t underestimate the determination of your dog—or someone else’s—to reproduce. Extra vigilance is needed; trust me, just because you have a fenced-in yard, that doesn’t mean anything!
Having dogs spayed, which involves removing the ovaries and/or uterus, is the most common and effective method for preventing unwanted dog pregnancies and reducing pet overpopulation. Sterilization is permanent and cannot be reversed.
From dog diapers to body wraps, there are multiple at-home, nonpermanent ways to prevent pregnancy. Do not frequent dog parks or other dog-populated areas while your dog is in heat. Additionally, if you choose to use a dog diaper, keep in mind it should be leakproof, absorbent, comfortable, and most importantly, secure. It should also be changed frequently.
Featured Image: iStock.com/Capuski
Help us make PetMD better
Was this article helpful?