Do Girl Dogs Get Periods? Canine Estrous Cycle

So, do girl dogs get periods? And how long do female dogs bleed while in heat? Yes, girl dogs get periods an average of once every six months and you can expect a female dog to bleed 4-15 days during the heat. Dog breed, dog size, and individual doggie differences will ultimately determine these numbers.

girl dogs periods bleed heat
Girl Dogs Periods Bleed Heat

While there are a lot of similarities between canines and humans, there are also a lot of differences. Dogs, for example, don’t have to worry about Lyme Disease nearly as much as humans do because they produce their own vitamin C every day.

But what about reproduction and menstrual cycles in dogs? Do dogs and humans share anything in common or do the differences outweigh the similarities? That’s what we’re going to discuss in this post.

Dogs will start bleeding in their heat cycle during the proestrus and estrus stages. You can expect some vaginal swelling and the discharge of red blood cells. 

On average, the blood is fairly minimal, but this again depends on several variables such as:

  • breed
  • size
  • individual doggie differences

A big difference with dogs is that bleeding in female dogs indicates the beginning of the cycle as opposed to the end in human females.

female dog with blue eyes up close

Related Reading: Dog Care Tips & Health Information For First Time Pet Parents

When Do Girl Dogs Get Their Period

Can girl dogs get periods? Absolutely, but it’s usually referred to as “in heat”. They get them first during two stages of their estrous cycle. Confused by the jargon? Me too. Let’s back up a bit.

The estrous cycle is the technical term for “a dog in heat”. Basically, the heat cycle is how the hormones rise and fall in a female dog. In humans, this roller coaster runs its loop about every 28 days, but with dogs, it can run anywhere from 3 – 6 months (the average is twice a year).

There are 4 stages to the estrous cycle:

StageAvg. Length
Proestrus5-7 days
Estrus7-9 days
Diestrus2 months
Anestrus3-4 months

You will find below, in greater detail, the four stages of the reproductive cycle (estrous cycle) in female dogs and what you can expect during each stage.

A Dog’s First Period: What to Expect

Since you’re here reading this post, you may be wondering what age female dogs start their period. Well, I’m sure you’re getting sick of hearing this by now, but, it depends.

Female dogs can go into heat as young as four months in smaller breeds. But on average, and with more medium to larger-sized dogs, you can expect a female dog to get their first period at around 6 months of age. Keep in mind, however, it’s referred to as “their first heat” rather than “their first period”.

It’s also not uncommon for female dogs of much larger breeds to get their first period as late as 2 years old.

Pet Parent Tip: if you’re planning on breeding your female dog it’s best practice to wait until their third heat cycle.

A female dog’s first heat cycle is unlikely to result in pregnancy due to both the dog and eggs not yet being fully mature. I mean, from my perspective, do you really want a 3-6-month-old puppy to be pregnant so fast? Let them live their doggie life for a little bit before becoming parents themselves.

Estrous Cycle In Dogs Explained


This is the beginning of the cycle. This is marked by a swollen vulva (female genitalia) and one of the two physical signs of the heat cycle.

This is when males will start to show interest when her personality will start to change a bit, and when she will start playing more “sexual” games with others. Mounting and chasing behaviour will start to become more pronounced.

Your dog will also have some slight bleeding from her genitalia. This could be compared to a period in a human, but this is actually the beginning, not the end of the cycle, unlike humans.

This bleeding is the second physical sign of the estrous cycle and will taper off around 5-7 days (this time can be shorter or longer, however).

Important: Heavy bleeding or bleeding outside of the heat cycle is not normal for female dogs. If you have any concerns around this please have your doggie checked out by a vet as soon as possible.


Your dog will continue to have a swollen vulva, and the discharge will be lighter, eventually becoming more clear although it is not urine. This is when males could become aggressive to try to mate with her as this is the time when a female dog can become pregnant.

You may have heard stories from pet parents of male dogs trying to break into homes to get to a female in heat. So it’s never a bad idea to “be on the lookout” during this time, especially if you’re trying to avoid a pregnant doggie.

Your female will usually be more willing to “play” with unknown males and will be more likely to let a known male mount her. However, if she absolutely hates a particular male, even though the hormones will push her breeding instinct, she may not let him mount her.

You may notice some changes in her personality at this point as well, but this varies on the personality of your dog.

This part of the heat cycle will usually last about 7-9 days (but again, it can differentiate by being as few as 3 days or as many as 21 days).

You will know if she is receptive to males by scratching above her tail. If she moves her tail to the side, she may be receptive to males. Do NOT let her go outside unsupervised.

Untethered males will jump fences, dig under them, and do anything they need to get at a receptive female, including attacking humans.


This is the time after her heat and will last the length of a typical dog pregnancy (about 54-60 days). Whether she gets pregnant or not, this will still last about two months. Unlike with humans, pregnancy does not interrupt the estrus cycle.

The discharge will end, and the swelling of her vulva will return to normal.

Your dog’s personality will return to normal, and the males will no longer be hounding your dog. Some dogs may experience pseudopregnancy during this time. This is a false pregnancy, and while it is not usually anything to worry about if you are concerned, you can see your vet about it.

She may have lactation and my mommy any stuffed animals she has access to. While this is not typical, it is normal. If your girl has packmates, she may protect her “puppies” from them which may result in some arguments between them, especially if one of the stuffed animals is a favourite of a packmate.


This is basically a lack of hormonal activity. Play will go back to normal. Your dog will no longer be protecting her stuffed animals as the hormones responsible for pseudopregnancy are no longer existent.

If she was pregnant, she would be caring for puppies for about half of this time. The time of this stage can last from about 30 to 90 days.

Dog Heat Cycle and Bleeding

You may be wondering how long your dog will bleed while in heat. Determining how long female dogs bleed while in heat, and more precisely how long your female dog will bleed while in heat is not an exact science.

But there are certainly some guidelines and averages that can help you better understand.

On average, you can expect a female dog to bleed for about two weeks while they are in heat. It could be shorter or it could be longer, there are several variables to consider and each doggie is unique.

If you read the previous section you’ll be aware that female dogs start bleeding during the first stage of heat which is the proestrus stage. The average here is around 9 days, but it can also last upwards of 20 days.

After the proestrus stage, a female dog will enter the estrus stage (the stage where they can become pregnant after mating). Your dog will still have discharge from her vagina but the amount will lessen and the colour will be lighter.

But for the most part, pet parents don’t need to worry too much. Your female dog will be in heat roughly twice a year and the two weeks of bleeding will likely be minimal, with about half of that time being less and less bleeding and vaginal discharge.

How Long Do Female Dogs Have Their Period?

Although the term “female dog period” is a frequently searched term, I’ll again state that it’s better to consider it a “heat cycle”. But I suppose, at the end of the day, it’s semantics (to a degree).

If you’re wondering how long are female dogs on their period then you’re probably either a new pet parent to a female dog or are finding yourself dealing with your first female dog period. Don’t panic, this is a normal and healthy process for all female dogs.

As I discussed above, there are four stages to a female dog’s reproductive cycle (estrous cycle).

The first two stages, proestrus, and estrus stages are when she will be in heat, or, “on her period”, and this will typically last 2-4 weeks.

The proestrus is the beginning of the heat cycle. This is marked by a swollen vulva (female genitalia) and one of the two physical signs of the heat cycle. Your dog will also have some slight bleeding from her genitalia.

This bleeding is the second physical sign of the proestrus cycle and will taper off around 5-7 days (this time can be shorter or longer, however).

During the estrus cycle, your dog will continue to have a swollen vulva, and the discharge will be lighter, eventually becoming more clear (although it is not urine).

This part of the heat cycle will usually last about 7-9 days (but again, it can differentiate by being as few as 3 days or as many as 21 days).

So, how long are dog periods? Well, girl dog periods happen during the proestrus and estrus stages of the estrus cycle (so much jargon!). And these two stages, on average, last around 2-4 weeks.

Frequently Asked Questions

Here are some more frequently asked questions relating to dogs and their reproductive cycle.

Do All Female Dogs Have Periods?

All doggies are different. The vast majority of female dogs who have not been spayed will go into heat, or, “have periods”.

There are some female dogs who experience infertility. If a female dog has not had their first heat cycle by 24 months of age then it would likely be diagnosed by a vet as having a condition such as Primary Persistent Anestrus. This condition can be caused by several different factors:

  • malnutrition
  • excessive physical activity
  • excessive lack of physical activity
  • medications interfering with fertility
  • isolation from other cycling female dogs
  • genetics
  • hormonal disorders
  • autoimmune diseases

If a female dog IS spayed then she will not go into heat. An exception to this is a condition called Ovarian Remnant Syndrome. This is a condition that affects female dogs who have been spayed and where some of the ovarian tissue remains in the body which can cause the production of estrogen and lead to signs of heat.

Can a Female Dog Go Into Heat Without Bleeding?

Yes, a female dog can go into heat without bleeding. This is known by veterinarians as “silent heat”, or subestrus.

Silent heat is when the external signs of the proestrus and estrus stages are not visible. That means there will be no vaginal discharge and will likely result in no interest from male dogs.

This is more common in younger and smaller breed dogs during their first few cycles, but that doesn’t rule out other female dogs.

Will a Spayed Female Dog Still Have a Period?

If you’re a pet parent to a female dog that wants to completely avoid having to deal with its heat cycle and have no intention of breeding her, then you may be considering having her spayed.

A spayed female dog will not have a period, or more correctly, will not go into heat.

Spay means “sterile”, and a sterile female dog has had its entire reproductive tract surgically removed. This means they no longer have ovaries or a uterus and will not go into heat.

But as previously stated, an exception to this is a condition called Ovarian Remnant Syndrome.

Why Do Female Dogs Bleed During Their Heat Cycle?

Ready for an answer full of jargon? Well, it’s difficult to answer this question in any other way. Fortunately, David J. Shuman, DVM Veterinary Medicine, answered this question on Quora:

“The bleeding is caused by the passage of blood cells through the intact walls of the uterine capillaries, typically accompanying inflammation due to the effects of estrodiol hormone during the three active portions of the dog’s estral cycle.

Unlike humans, there is no sloughing of the endometrial lining. This is more of a passive event- where blood is leaching through -than an active one so there is no cramping or discomfort associated with muscle contraction and spasm.

During Proestrus, estradiol increases to peak just before ovulation. As it peaks there is a sharp increase in Luteinizing Hormone (LH) for 24–72 hours and the initiation of an increase in progesterone which plateau’s at 10–30 days after this LH peak.

As these two hormones climb estradiol decreases but don’t yet fully disappear. This is the reason why the initial onset of estral bleeding decreases but doesn’t fully go away when the female actually ovulates.”

Thanks, David, you just saved me hours of research…

A vet doctor putting a diaper on a female dog having a period
A vet doctor putting a diaper on a female dog having a period

Dog Bleeding From Vulva But She’s Not In Heat?

When pet parents take to the internet with questions like “My dog’s vag is swollen and bleeding” they are often in a panicked state. Often, however, their dog is simply starting their heat cycle.

But if a female dog is definitely not in their heat cycle yet still experiencing bleeding from their vagina it could be due to several reasons, such as:

  • Pyometra
  • Miscarriage
  • Vaginal Inflammation
  • Tumours of the vagina

The only way to know for sure is to take your doggie to a veterinarian. If you’re a new pet parent and want to avoid any of these possible complications then consider having your female doggie spayed.

How Long Does a Dog Bleed After Having Puppies and Giving Birth

Some pet parents are surprised to learn that their doggie may continue bleeding for a while after they give birth. If you’re not prepared, this may cause some staining in unwanted places.

It is normal for a female dog to continue spotting (bleeding from vagina) for up to several weeks after giving birth.

It’s important to keep a close eye on your dog during this time and monitor their genitalia to determine if everything is healthy. There are some serious conditions that can arise after a dog gives birth, and abnormalities in their vaginal bleeding and spotting are often the first sign.

Here’s a list of various Post Partum Complications that female dogs can experience:

  • Retained Foetal Membrane
  • Subinvolution of Placental Sites
  • Post-Partum Metritis
  • Post-Partum Haemorrhage
  • Eclampsia
  • Mastitis
  • Prolapsed Uterus

While many of these conditions are on the rare side, it is always best practice to take your doggie to a vet if you suspect anything has gone wrong following their birth.

Final Notes

I hope this post has put some nerves at ease. New pet parents often take to the internet in times of crisis or curiosity.

A danger with this tactic, however, is it often leads to contradictions and more questions as the internet is seemingly infinite.

And remember, if you’re ever concerned and unsure how to care for your doggie, visit a veterinarian asap.

stuart and his dog

Family Dog Expert Author

Hi there! I’m Stuart, a devoted dog lover and family dog expert with over a decade of experience working with our furry companions. My passion for dogs drives me to share my knowledge and expertise, helping families build strong, loving bonds with their four-legged friends. When I’m not writing for SirDoggie, you’ll find me hiking, playing with my beautiful dog, or studying music.