Learn about members of the Animal Kingdom

How Often Do Dogs Go Into Heat?

A dog in heat can be grumpy in the first week of the cycle

Medium and large dog breeds go into heat once or two times per year, while small dog breeds can go into heat up to three times per year. However, not all dogs at the same date or even month, so stay tuned to find out how often do dogs go into heat?

When Do Dogs Come Into Heat?

If you have a puppy (female), you will be probably very interested to know when her heat cycle starts, because when this will happen, even if you keep her in the house or outside in the yard, she will start to leave blood stains all over the house or outside on your porch.

Puppies will start going into heat around six months old, and then around two years old, their regular heat cycle will start.

Large dog breeds can go into heat only once a year or twice a year, so every six months or every twelve months.

Small dog breeds (toy dog breeds) can go into heat more often (up to three times a year), but normally all dogs go into heat twice a year.

How To Recognize A Dog In Heat?

There are several clinical signs that can show you when your dog is in heat.

The first thing to notice is a bloody or straw colored discharge coming from its vulva, and the next thing to notice is the swollen vulva that gets larger in size.

Later, you can notice the tail position. It might become erect, or pulled to the side.

The behavior is also changed, because some dogs become agitated (more active) seeking out a male (due to the hormonal changes in their body).

You can also notice that your dog starts cleaning herself more often, and becomes more affectionate, so remember to set aside some time to pet your dog and show her love.

Stages Of Heat In Dogs

Most dogs go into heat twice a year, or every six months. There are four different stages of heat cycle: proestrus, estrus, diestrus, and anestrus.


The proestrus stage marks the beginning of the bleeding and lasts nine or ten days.
During this stage, the female will urinate more often and her vulva will become swollen.


The estrus stage is the stage when your dog gets interested in males. This is the time period when you have to keep a close eye on your female if you don’t plan to breed her.


In the diestrus stage, your dog will experience different changes in her body. A lot of ovarian activity occurs during this stage.

This stage typically lasts six to ten weeks.


The final stage called the anestrus stage is the time during when your dog does not have any hormonal activity.

How Long Does The Heat Cycle Last And How To Care For A Female In Heat?

The heat cycle in dogs can last between two and four weeks. Normally, it lasts about a full month, so be prepared for breeding for about 30 days.

During this time period, you have to keep her very comfortable to avoid being more agitated. A female in heat is more agitated and starts pacing, whimpering and panting.

It is best to separate the female from other dogs during the cycle period.

You will know that the heat cycle is over, when the vulva goes back to the normal size, and the bleeding stops.

When Is The Best Time To Breed A Dog?

If you are looking to breed your dog or dogs, you have to know that your dog starts becoming more receptive to males around day nine and ten in the heat cycle (while in estrus).

In the first week of heat, your female dog will not be very interested in male dogs, however, in the second week of heat, she will suddenly become quite interested in male dogs starting with day nine or ten in the heat cycle. Your dog will accept males for about five days, and after that she will start rejecting them.

If you want to avoid any heat cycles at all, and you don’t want to breed your dog, you have to spay your pet with your local veterinarian.

You can spay your dog from around four months old to six months old, and this way you will also avoid the first heat cycle.

When Do Most Dogs Go Into Heat?

The first heat cycle in dogs starts between the age of 6 and 12 months, however, small dog breeds go into heat earlier (at the age of 6 months), while large dog breeds can have their first estrus between the age of 12 and 24 months.

Females become more interested in males during estrus

Females become more interested in males during estrus, image source: unsplash.com

If a large dog breed female grows next to a male, the first heat cycle can occur at the age of nine months, however, if the female grows without the presence of a male, the first heat cycle will occur much later at one year of age or even later.

Will My Dog Change After Her First Heat?

After having her first heat cycle, your female dog is becoming more mature, so instead of acting like a puppy, she will become more affectionate or grumpy.

She can even start eating more food or less food. However, after the first heat cycle, your female will no longer be the same dog she was before, due to the hormonal changes in her body that are taking place during the diestrus stage in her heat cycle.

How Long Do You Have To Wait To Spay A Dog After Heat?

If you want to spay your dog it is best to do it before her first heat cycle (before the age of 6 months) because this way you can reduce the risk of mammary tumors.

However, if the first heat cycle already happened, you can still spay your dog. Spaying your dog will greatly reduce her drive to roam while in heat. You will also avoid any future irritable and nervous behavior produced by pain during ovulation in females that haven’t been spayed.

Your veterinarian will recommend to wait about two to three months after the ending of the last heat cycle to spay your dog.

Neutering or spaying your dog is not a dog problem, is mostly a people problem because it’s our responsibility to make sure that our dogs are not roaming and having unplanned litters.


The only people that should breed dogs are qualified, responsible and ethical breeders.

You have to understand that if you decide not to spay or neuter your dog, you are also making the commitment that your dog or dogs will not going to be part of the huge pet overpopulation problem we have in the United States or other parts of the world.

This is not just some commitment, it is actually a pretty huge one, because only we as humans are solely responsible for the uncontrolled breeding of dogs in the community.

Article written by:

Darius Savin is a lifelong animal lover and protector and the chief editor of Checkmember. He writes and edits articles and is also the creator of the distribution maps for all the creatures featured here.