Dogs in Heat: Frequently Asked Questions

When a female dog is “in heat” or “going into heat,” it means she’s open and receptive to mating and is releasing mating hormones. Some signs of a female dog going into heat may include lower energy levels, more aggressive behavior, differences in leg-raising while urinating, urinating more often than usual, and even running away from home. This is unlike male dogs, who do not experience heat cycles.

Unawareness that your dog is going into heat or not knowing what to look for can result in an unwanted pregnancy. However, learning what to do when your dog is in heat will help you properly prepare for a new furry family member should you desire the pregnancy instead.

What Is the Dog Heat Cycle?

The dog heat cycle, also known as the estrus cycle, is a biological event where a female dog is most receptive to mating. It usually lasts anywhere between two and four weeks, and a female dog will experience this about every six months. A dog in heat may exhibit strange personality and physiological changes throughout the cycle.

There are four stages:

• The proestrus stage: This is the first stage of a dog’s heat cycle and usually begins with the swelling of the vulva. It can last anywhere from three to 17 days. A female dog in this stage of the heat cycle is resistant to male company and may exhibit changes in personality, appetite, and more frequent tail tucking.
• The estrus stage: A female dog will begin to naturally follow her breeding instinct in the estrus stage of her heat cycle. She is the most fertile here as her ovaries release eggs for fertilization and she is most willing to accept male company in this stage. She’ll raise her rear toward male dogs and may remain in this stage for between three and 17 days.
• The diestrus stage: In this stage, the dog’s heat cycle begins to come to an end. If a female dog entering this stage has been impregnated, this stage will last from the end of the estrus stage up until her puppies are born (dogs are pregnant for about 60 days). A female dog will not flirt as much and her swelling will decrease gradually.
• The anestrus stage: This is the stage of the dog’s heat cycle that lasts the longest, anywhere between 100 and 150 days. The anestrus stage is also known as the resting stage. The dog’s heat cycle starts again after this stage.

Study each stage to help you identify when your female furry friend may be going into heat.

How Often Are Dogs in Heat?

Female dogs will often go into heat once every six months (or about twice a year), but the breed size of the dog also affects the frequency of the cycle: a smaller dog may go into heat more often than a larger dog, and a dog’s heat cycles may seem irregular when they first start to experience them.

How Long Are Dogs in Heat?

The proestrus and estrus stages of the dog’s heat cycle can last anywhere from two to four weeks collectively. However, it may still vary as the cycle officially begins and ends with the swelling and return to normalcy of the vulva. The pregnancy status of a female dog will affect how long she remains in the diestrus stage; the anestrus stage of the dog’s heat cycle is simply the resting stage that intermits the next one.

When Do Dogs First Go Into Heat?

A female dog can first experience her heat cycle as early as six months of age, but this varies with breed. A smaller dog may first experience their heat cycle earlier than a larger dog, who may not experience theirs until up to two years of age. Female dogs will continue to experience heat cycles throughout their lives up until death, but the time between each cycle will increase with age. Female dogs don’t experience menopause.

How to Tell If a Dog Is in Heat

As a pet parent, it’s a good idea to verse yourself well on the signs of a dog entering their heat cycle. Common signs of a dog entering heat include:

• Frequent urination: This is one of the most common signs that a dog is entering heat, especially if they’re uncharacteristically urinating in the house.
• Vaginal bleeding and/or discharges: A female dog entering heat may lightly discharge and/or bleed from her vagina while entering the proestrus stage. The bleeding will grow heavier and lighten in color as she enters the estrus stage.
• More attention paid to male dogs: If a female dog in heat sees a male dog, she’ll “flirt” with him by exposing and raising her rear in his direction while moving her tail out of the way.
• Excessive genital licking: A female dog in heat will excessively lick (or “clean”) her genital area.
• Nervously aggressive behavior: Since a female dog in heat is secreting mating hormones, she may exhibit unusually aggressive behavior.

Other signs of a dog in heat include tail tucking and the swelling of the vulva.

What to Do When Your Dog Is in Heat

You should never panic if you notice your dog entering her heat cycle; it’s a very natural occurrence! There are simple steps you can take to make sure your dog gets the special care she’ll need.

• Do not leave your dog outside and unsupervised: A female dog in heat who’s also outside and alone is the perfect company for a passerby (or stray) male dog looking to mate.
• Walk your dog with a leash: To safely walk your dog while she’s in heat, you should always keep her on a leash despite her obedience skills. A female dog in heat will be heavily influenced by her hormones.
• Increase indoor supervision: You should stay mindful of your dog’s whereabouts and keep her off furniture, as she may naturally leave some blood spotting behind and potentially stain surfaces. Pads can also be used to allow her to enjoy her preferred resting spot without the risk of leaving stains behind on furniture or carpet, and providing for easier cleanup at regular intervals.
• Use diapers and washable diaper liners to prevent messes: Some bleeding or bloody discharge is normal during her time in heat, and she will likely have the need to urinate more frequently than you are used to. Use diapers to contain and prevent messes, and help both of you navigate this period without unwanted stains or accidents. There are multiple types of diapers for dogs in heat to choose from, including disposable and reusable garments. Wee-Wee Disposable diapers work much like a diaper for a human infant, plus include a special opening to accommodate your pet’s tail. They’re available in multiple sizes so you can find the one that’s right for your dog, ranging from X-Small to X-Large. Proper sizing is important to prevent leakage.

Deploying these four care tactics when your dog is in heat will ensure she has a safe, clean, and manageable experience. Dogs aren't the only furry friends who experience this natural cycle! Learn all about cats in heat.