Dog Knowledge

How Long Does a Dog Stay in Heat? What Pet Parents Should Know

Written By: Tiffany Ruiz Dasilva, VMD, cVMA | Professional Services Veterinarian, Wild Earth

It’s a girl! Congratulations on your new puppy. Now is the time to read up on everything you need to know about her upcoming life stages, including when she reaches sexual maturity and experiences her first estrous cycle, or heat cycle. .

When a dog is in their estrous cycle, or heat, her estrogen levels increase and then sharply decrease, releasing mature eggs from the dog’s ovaries. Along with these hormonal changes, a female dog will also experience behavioral and physical changes.

In this article we will go through  everything you need to know about a female dog’s reproductive cycle, what you need to do during her first time in the heat, and help you gauge the best time to get her fixed.

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What It Means When a Dog Is “in Heat”

When a dog is “in heat” this means they are able to get pregnant. On average, a dog will reach sexual maturity and experience their first “heat” around 6 months of age, although this can occur sooner for smaller dogs and as late as two years of age for larger dogs. Female dogs will then go into heat approximately every six to twelve months.

How Can I Tell If My Dog Is in Heat?

The first sign pet parents typically notice when their dog is in heat is bloody vaginal discharge, which usually starts a few days after they have entered their estrous cycle. The amount of discharge varies from dog to dog. Usually vaginal swelling occurs before discharge, but is not typically noticed. In addition to hormonal and physical changes, dogs in heat may also experience behavioral changes such as more frequent urination or marking behavior, and increased licking of their vulva.

two dogs looking up at the camera

How Can I Tell If My Dog Is in Heat?

The first sign pet parents typically notice when their dog is in heat is bloody vaginal discharge, which usually starts a few days after they have entered their estrous cycle. The amount of discharge varies from dog to dog. Usually vaginal swelling occurs before discharge, but is not typically noticed. In addition to hormonal and physical changes, dogs in heat may also experience behavioral changes such as more frequent urination or marking behavior, and increased licking of their vulva.

One of the first telltale signs of a dog in heat is personality and behavior changes due to the shift in their hormone levels. There are three stages of a dog in estrus that are detailed below: proestrus, estrus, and diestrus.

How Long Does a Dog Stay in Heat?

Each heat cycle lasts about two to three weeks on average. As mentioned, the first signs you may notice are vulvar discharge and swelling, and when it is over the vulva returns to its normal size and there is no more discharge. There are three stages of the heat cycle that are detailed below: Proestrus, Estrus, and Diestrus.

Stage 1: Proestrus

Proestrus lasts about one week, and although female dogs will attract males, have vulvar swelling and initial bloody discharge, they will not be receptive to mating during this time. 

Stage 2: Estrus

Estrus is characterized by clear or brownish discharge, and at this time females will be receptive to mating. A female dog may indicate she is ready to mate by flaunting her rear in front of other dogs or fanning her tail in order to spread the scent of her pheromones around. She may also urinate more frequently or begin marking territory to spread her scent even more.

Stage 3: Diestrus

Diestrus occurs around day 14 of the heat cycle, and at this time discharge will cease and the vulva will return to its normal size.

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In Between Heat Cycles: Anestrus

The time between diestrus and the next proestrus is called anestrus. During this time the body prepares itself for the next cycle. 

Now that you know the signs and stages of a female dog in heat, you need to know what actions you need to take as a dog parent during this time. Read on for information on how to care for a dog in heat in the next section.

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What Do I Need to Do When My Dog Is in Heat?

Avoid all contact with intact (not neutered) male dogs while your female dog is in heat. Pheromones are very powerful during the estrus stage, and can be smelled by other dogs from miles away. .

A male dog may try to mount your dog while in estrus, and an intact dog can get your dog pregnant while in heat, so be sure to keep a close eye on your dog during this time.

Other steps to take in order to avoid unwanted pregnancy include leash walks and supervision while in the yard. You don’t want your pup to get caught up with a male dog while off-leash, so it is best to avoid the dog park in particular.

As mentioned, there will be some bloody discharge when your dog is in heat, and will likely groom herself during this time by licking. Do not discourage this behavior as it is normal. 

When to Spay?

Spaying has many benefits, most notably preventing cancer, uterine infections, and animal homelessness. Additionally, spaying and neutering has also been shown to increase lifespan, helping dogs live longer lives. While there is no argument on the benefits of spaying, many pet parents are confused by when it is best to spay. There is evidence to support that larger breed dogs may benefit from being spayed after their first heat, but it is important to note that dogs can get pregnant during their first heat. Furthermore, contrary to popular myths, there are no valid reasons for allowing a dog to have a litter of puppies before spaying her. Speak to your veterinarian about when it is best to spay your dog depending on their breed and size. 

Final Words on the Female Dog’s Reproductive Cycle

The whole process of managing a dog in heat may seem daunting at first, but it’s a totally normal and natural process of their lives. Consider spaying your dog, and remember there are many health benefits and added advantages to having her fixed.

Tiffany Ruiz Dasilva, VMD, cVMA

Dr. Tiffany Ruiz Dasilva is the Professional Services Veterinarian here at Wild Earth. She received her Bachelor of Science degree in Biology from Brown University, and attended veterinary school at the University of Pennsylvania School of Veterinary Medicine. Since graduation, she has worked in general practice, on telehealth platforms, and in animal rehabilitation. She has worked tirelessly to gain expertise in the field of canine nutrition through numerous certifications and coursework, and plans to pursue her Masters in Animal Nutrition.

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