What are the Stages of a Dog in Heat?

Posted by Dr. Roth on

Dog laying down, what are the stages of a dog in heat
A female dog who hasn’t been spayed can go into a state of fertility called heat. Female dogs are only fertile about twice a year when they are in heat, in which their bodies are prepared to make puppies. 

To prevent surprise pregnancies and to ensure their dog is comfortable and healthy during the process, pet parents need to understand the stages of a dog in heat. 

What Are the Stages of a Dog in Heat?

The entire canine estrous cycle is made up of four different stages, proestrus stage, estrus stage, diestrus stage, and anestrus stage. The estrus stage refers to when a dog can become pregnant and is said to be “in heat.” A dog will probably have her first heat when she’s four to six months old. and it will come back every six months or so unless she is spayed. This interval can vary between breeds. Every cycle, she’ll go through each of the four stages.

Proestrus Stage

This is the very beginning of a dog’s heat.

During proestrus a dog probably can’t get pregnant, but there’s always a chance. Pet parents should start keeping their dog inside and away from male dogs at this time.

Proestrus can last from four days to three weeks. If she is not spayed, her hormones will trigger changes in her body, including discharge that causes her to start licking and rubbing herself. If a pet parent notices swelling and reddish discharge from their dog’s vulva, then she’s probably just gone into heat.

Estrus Stage

The estrus stage is when a dog is most fertile.

The estrus stage lasts between five and fourteen days. It’s crucial that she is kept away from male dogs at this point. They can smell when a female dog is in heat, and their natural instinct is to try to get close to her. Keeping a pet inside is the best option to prevent pregnancies. 

At this point, her behavior will probably change. She may become much more affectionate with pet parents and other pets. She may also start whining to go outside more often. Her discharge will become more yellow instead of red. 

Diestrus Stage

Once a dog is no longer fertile, she’ll be in the diestrus stage. This can last sixty to ninety days. She’ll still attract the attention of male dogs, but she shouldn't be able to get pregnant anymore. Her discharge will become red again, then stop altogether. 

Anestrus Stage

The anestrus stage is the time when a dog is not in heat and behaves normally. This stage lasts four to six months. 

If a dog is spayed, then her hormones will never trigger the beginning of a heat cycle. She’ll remain in the anestrus stage and will not experience any of the symptoms or risks of going into heat. It is common dog health advice for pet parents to spay their pets early. The procedure will eliminate the possibility of pregnancy and can also reduce the risk of a dog developing uterine infections, mammary tumors, and cancer. 

Dog Care During Heat

Being in heat isn’t always comfortable for a dog. The best things pet parents can do are to give their dogs lots of love, a comfortable environment, and keep them inside. When their dog is outside, pet parents should be on the lookout for other dogs in or near the yard. With just a few precautions, an unspayed pet will get through her heat safe and sound. 

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