How to tell if your dog is in heat? Here's everything you need to know

How to tell if your dog is in heat? Here's everything you need to know

When does a dog experience her first estrus?

The first estrus generally occurs when an unspayed female dog is between 6 and 24 months old. It tends to occur earlier for small-breed dogs and later for large-breed dogs.  

How often do dogs go into heat?

dog in heat

It depends on your dog's breed, as it varies with different breeds and individual dogs, an unspayed female usually goes into heat twice yearly, about every six months.

How long does a dog stay in heat?

The time during which male dogs are attracted to a female dog is variable, approximately 18 days. Females are receptive to males for only half of this time.

How can you tell if your dog is in heat? 

When your dog is in heat, it will appear nervous, easily distracted, and more alert. She may urinate more often than she normally does. You'll most probably notice changes in her behavior, this is caused by a shift in hormone balance. When a female dog is ready to breed, she may initiate sexual interactions with other dogs. 

At first, vaginal discharge is blood-tinged and the vulva is swollen. When the female is receptive to males, vaginal discharge decreases and is straw-colored.

4 stage of dog heat cycle

Picture credit: the spruce 

4 stages of the dog heat cycle

Proestrus stage 

The first stage of the heat cycle is called proestrus. It can last from 3 to17 days, but many dogs experience about 9 days in proestrus. The best way to spot the beginning of a dog heat cycle is the swelling of the vulva. You may notice the following symptoms during this stage:

Changes in Personality

Changes can range from mild to more severe. Sometimes a female dog will become more affectionate and clingy with her owner, but other times she may seem grumpy.   

Changes in Appetite 

During this first week, she may get even hungrier, hence you might want to increase its food portion. Whatever the change is, taking note of it can be a significant clue that the heat cycle has begun. 

Tail Tucking 

It is a reaction to guard the vulva, either by tucking the tail between the leg or sitting down whenever another dog approaches. 

Swelling Vulva 

The amount of vulva swelling varies. Some dogs swell just a bit, while others swell quite a lot. Typically the bleeding is light during the first few days when it comes to mid-week, it grows a bit heavier

Estrus stage

It typically lasts from 3-21 days and lasts 9 days on average. This is the time your dog is fertile and the ovaries begin to release eggs for fertilization. The female dog will be willing to accept the male's company, she might try to be outside more often than normal. During this period, her symptoms include:

Lightened discharge:

Previously, it is bright red, the discharge now lightens to be pink-ish. 

Softening of the vulva 

Initial swelling subsides just enough to make the vulva soften enough for penetration.


She will be inviting the male by turning her rear toward him and holding the tail high and out of the way. If there's no male dog next to her, she might find a way to leave the house. 

Diestrus stage

The Diestrus stage is towards the end of the heat cycle. This stage can last from 60-90 days, at this point, the dog is no longer fertile. If the dog has been impregnated, the diestrus stage lasts from the end of the estrus until the birth of the puppies. Here are the signs :

Gradual disappearance of vulva swelling

Most of the swelling is gone at this stage, but the vulva may remain slightly large. 

Less flirting 

Put aside whether she is pregnant or not, the dog now lacks the "mood" to mate and is no longer interested in flirting. 

Anestrus stage 

Anestrus is the final stage of the dog heat cycle. This is the longest phase throughout the whole cycle, from 100-150 days, at the end of which the entire heat cycle starts again. 

At what stage of the estrus cycle is the dog able to pregnant?

The female dog usually ovulates at the time where the vaginal discharge becomes watery; this marks her most fertile stage and is the time where she will be most receptive to breeding. However, sperm can survive for 1 week and be capable of fertilizing the eggs, so it's possible for her to get pregnant while she is in estrus. 

How can you prevent your dog from going into heat?

Spayed is the most highly recommended way to prevent estrus and pregnancy, not only that but to protect her against breast cancer and disease of the reproductive system. You may spay your dog as young as 2 months old, but it is best to consult with your veterinarian for specific recommendations.

dog mismated

What if your dog has been mismated, or accidentally mates with another dog?

You will need to contact your veterinarian as soon as possible. There are mismating injections within the first to two days after mating, but there are risks that you will need to discuss it with your veterinarian.

At what age should I spay my dog? 

Although veterinarians used to recommend spaying your dog as young as 4 months old to ensure she never experienced a heat cycle to prevent mammary cancer. You should discuss any health concerns with your veterinarians before discussing what age is appropriate to spay your dog. 

If you think that your dog is sick, consult your veterinarian as soon as possible, as they have examined your pet, know your pet's history, hence they can make the best recommendations for your pet.

Does a dog go through a menopause? 

No, dogs do not go through menopause like humans. Dogs that have not been spayed will continue to have heat cycles and therefore bleed once a twice a year, or their entire lives unless they are pregnant or get spayed. 

Can I walk my dog when she's in heat?

Yes, you can walk your dog when she's in heat, and for owners who don't have a backyard, you must walk your dog. Taking your dog for a dog is one of the ways to calm their mind when they're in heat. Other ways work too, but walking is a must. 

image 2017 revised how petbacker works


Petbacker Logo 

About PetBacker

PetBacker is a platform that lets you hire Pet Sitter and Pet Boarding Owner fast.

Find a Sitter Provide Pet Service