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A Dog’s Heat Cycle – When, Why, and How to Handle It?

Like all mammals, dogs have their reproductive cycles too. Female dogs tend to have periods after a few months per their breed. This might last for weeks, and during this phase, the dogs will be sexually active and ready to conceive. The female dog periods is called the heat cycle or estrous cycle in pets. The term heat refers to a period of ovulation when the female dog is fertile to breed and get pregnant. While this is a biologically inevitable process, the right information can help owners make good choices for their dogs to prevent unwanted pregnancies and take care of them properly. Let us see how long does a dog stay in heat and what are the stages of dogs in heat.

Estrous Cycle in Dogs

The estrous cycle of your pet consists of four stages- 

Stage 1 – Proestrus

Initial signs of dog in heat ranges from 4-14 days but lasts an average of 9 days. Female dogs won’t be receptive to male dogs. Enlarged vulva with bloody discharge. Increased estrogen levels and signs of irritation and restlessness. A female dog will keep her tail close to her body and might attract dogs. But she won’t be receptive.

Stage 2 – Estrus Cycle in Dogs

In this one of the dog in heat stages, the female dog will show signs of receptiveness and courtship to male dogs. She will keep her tail tucked to her side and show physical signs of readiness, like moving her hindsight towards the male dogs. This particular cycle in dogs ranges from 4-25 days and lasts an average of 9 days. In female dogs, the fertile period is accompanied by clear behavioural signs. Due to a decrease in blood and estrogen levels, the vaginal discharge is clear pink in colour. 

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Stage 3 – Diestrus

End of the estrus, the female dog is no longer receptive to the male dog. Initial signs like swollen vulva and discharges fade away. The vulva is no longer swollen, and there is no discharge during this stage. The duration for this period is 60 days. Increased levels of progesterone decrease gradually with the end of this period. There is a decrease in estrogen levels.

Stage 4 – Anestrus in Dogs

Period of reproductive and sexual inactivity. In this stage, ovaries do not produce eggs. Anestrus phase in canines is the duration period after the diestrus and before the next proestrus. This stage range is for 100 or more days. Here, the vulva is reduced to normal size, and there will be no vaginal discharge.

Signs & Symptoms of a Dog in Heat

There are clear signs of female dog in heat that can be used to determine the cycle’s onset and take the right measures for the same. Some of the most common and general symptoms of dog in heat are-

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  • Swollen or enlarged vulva
  • Irritation and restless behaviour
  • Bloody discharge 
  • Licking of the genital area more than usual days
  • Frequent urination
  • Tail tucked under legs too often
  • Receptive behaviour towards dogs
  • Humping or mounting acts

When Does Heat Start in Female Dogs?

Now, how long does a female dog stay in heat? The dogs first heat cycle starts at different times depending on their breed and size. While in the case of Smaller dogs, heat occurs as early as the age of 4 months, in the case of larger dogs, it usually happens when they are 18 to 24 months old. Generally, one should expect the first heat in their dog when they are around 6-7 months of age. Thus, the heat period can start at various points of the lifecycle in different breeds of dogs. Heat can start from as early as 6 months to as late as 1 year.

How Often Do Dogs Go into Heat?

Want to know the regularity of dogs going into the heat? Different canine breeds have different ages when puberty hits them and their heart cycle starts. Generally, female dogs come in an interval of every six months, that is, twice per year. But this cannot be taken as a standard period because, as mentioned, the cycle may vary with breeds. Dogs of smaller breeds have more frequent heat cycles. They can go into heat thrice a year. But in the case of larger breeds, it can be only once a year. 

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Furthermore, one should understand that the onset of heat is a process that could be more predictable in female dogs. When young female dogs start their cycle, it is irregular. But with age, it becomes regular. Generally, the cycle takes two to three years to become regular. Though there is no specific evidence to prove this fact, most dogs tend to have their heat cycle aligned to the months of spring and fall. Dogs tend to come into heat throughout their lifespan. But the gap between estrus and dormancy will widen with old age.

How Long Does a Dog Stay in Heat?

What is the time period of a dog’s heat? The period of heat in dogs lasts for 2-4 weeks. It begins with proestrus, when the female dog’s body gets prepared for later stages. She won’t be receptive towards the male dogs, but there will be other signs like swollen vulva and bloody discharge. Later on, as the cycles proceed, the level of sexual activity will reduce and finally, when the female dog reaches diestrus, the vulva will be at its normal size, and there will be no discharge. The fertility period in female dogs ranges from 5-6 days after 10 days from the onset of heat. She is most likely to get pregnant during this period. 

How to Prevent Heat in Dogs?

Now that you know when does female dogs go into heat it is time to understand the ways to prevent it. Heat cycles in dogs are stressful for owners. Not only do they have to deal with the cleanliness issues, but the behavioral changes and risks of unwanted pregnancies can prove quite inconvenient. There are ways to prevent a female dog heat cycle.

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The most recommended and conventional way to prevent the heat cycle in dogs is spaying which involves surgery to remove the uterus and other reproductive organs in your dog. Since, spaying in dogs is a permanent solution and cannot be reversed, the female dog won’t ever be able to conceive and give birth to a litter. Spaying is the best way to avoid pregnancy in dogs because it prevents several reproductive diseases, such as pyometra and genital cancer.

Another method is to provide medicines that can prevent unwanted pregnancy. The most common drugs, such as progestin megestrol acetate, are prescribed by vets. But these drugs cannot be used throughout the lifecycle of your dog. Additionally, they can prove to be harmful because they have side effects like kidney and liver issues, weight gain, hormonal imbalance, behavioural changes, and infections in mammary glands. Therefore it is advisable to go for spaying instead of using drug-based contraceptive methods.

Tips for Handling Heat Cycle in Dogs

Owners can always prepare well to care for their dogs during the heat cycle. Following these tips make it convenient both for the owner and dog to deal with the estrous cycle-

  • Buy a good quality dog diaper for female dogs. Female dogs tend to discharge a lot during the onset of their cycle, which might go on till the end of it. Therefore using a dog diaper may be necessary to prevent mess and unhygienic situations. Keep changing the diapers regularly to prevent infections and keep your female dog clean.
  • Provide washable disposable blankets to your dog during this phase to handle messy situations. 
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  • Take good care of your female dogs’ eating and drinking habits. Ensure that they get plenty of rest and nutrition during this phase since there will be a lot of irritation and restlessness owing to hormonal imbalance.
  • Avoid outdoor activities and walks to prevent male dogs from getting attracted to their female dogs. Try to take her out during hours when there won’t be many male dogs around.
  • Use a leash while walking your dog during the heat cycle to prevent nuisance.
  • Consult your veterinarian for extra precautions and tips to care for your female dog during the heat cycle.


It is important to understand that the estrous cycle is a natural and biological process inevitable in dogs. Therefore, one must be kind towards their pets during this phase. Not only are their pets dealing with many bodily changes, but there are also hormonal and behavioural changes that might be uncomfortable for the dogs. It is imperative not to scold or admonish dogs for things that aren’t in their control, like discharge and behavioral changes. Rather, owners should be generous and kind towards their dogs during this phase. Providing them with extra care and love will help strengthen the bond. Hopefully, with our guide all of your questions like how often do dogs go into heat, etc., are all clarified.