When Do Dogs Go Into Heat?

Dogs have their first heat when they reach puberty. However, this stage differs from dog to dog, typically depending on their size. Dogs typically enter their first cycle between six and 18 months. Small dogs can reach heat much sooner at around four months of age, medium dogs will be around six months old, and large dogs may be between 18 and 24 months before they have their first heat.

Whether you’re trying to prevent your dog from becoming pregnant or you plan to breed your dog, you must obtain a basic understanding of the heat cycle to take care of your dog’s health. Dogs experience behavioral changes and require special care during different stages of their cycle. Knowing what your dog needs and when to expect different behaviors or symptoms can help you make them more comfortable. 

This article will discuss how often dogs go into heat, the different stages of the heat cycle, signs your dog is in heat, and how to care for a dog throughout her cycle. 

• How Often Do Dogs Go Into Heat?
• How Do I Know When My Dog Is Going Into Heat?
• Prep For Going Into Heat
• What to Do After Heat
• Caring For Your Pup

How Often Do Dogs Go Into Heat?

Now that you understand when female dogs go into heat, you should learn how often they enter their heat cycles. After dogs begin estrus, they’ll go into heat every year. However, their first few cycles might be irregular until they’re fully matured. Most dogs go into heat twice per year, but smaller dogs can go into heat more often. 

On the other hand, large breeds may only go into heat once a year. After dogs reach maturity, it can take a few years for their bodies to develop regular cycles, so your dog might skip their cycle from time to time while they’re still young.¹

Once your dog has regular cycles, you can expect them to remain regular. However, the frequency of the cycles can slow down with age, even though female dogs go into heat throughout their entire lives. Therefore, your dog can get pregnant at any age once they’ve reached puberty. However, it’s more dangerous for older dogs to go through pregnancy, so learning more about the heat cycle can help you prevent pregnancy as they get older. 

Since heat cycles remain consistent after the first few years, you can expect your dog to have regular cycles every year, allowing you to track them and take better care of your dog.

The heat cycle

How long your dog’s heat cycle lasts and the duration of each stage of the cycle depends on their size, breed, and age. The dog heat cycle has four stages:

1. Proestrus (9 days)

The proestrus stage typically lasts anywhere from seven to ten days.² During this stage, dogs lick themselves more often because they experience vulvar swelling and red or brown discharge. Your dog may also exhibit behavioral changes like tail tucking or becoming less affectionate. During this part of the cycle, female dogs are not ready to mate. 

2. Estrus (9 days)

On average, the second stage, estrus, lasts around nine days.² During this stage, the vulva is still swollen, but there will be less discharge. Female dogs in the estrus stage may become more flirtatious with male dogs because this is when they’re fertile. 

3. Diestrus (60 days)

The diestrus stage lasts 60 days on average and occurs when the female is no longer fertile. During this stage, they’ll stop flirting with males and may even be pregnant already. 

4. Anestrus (6 months)

Anestrus is the stage in which your dog isn’t fertile, but they could already be pregnant from the earlier stages of their cycle.  

How Do I Know When My Dog Is Going Into Heat?

Over time, pet parents will become more aware of the signs their dog exhibits to indicate they’re going into heat. Also, since cycles become more regular over time, you will be able to track your dog’s next heat cycle to help you prepare. Early signs your dog is going into heat include:

• Vulvar swelling
• Vaginal discharge
• Tail tucking
• Clinginess or aggression towards owners and other dogs
• Changes in appetite

The first and most noticeable sign that your dog is about to begin their heat cycle is vaginal bleeding and swelling. Your dog may lick themselves to stay clean or manage any discomfort they’re feeling. 

Once your dog goes into heat and reaches the estrus stage, also known as the fertile stage of the heat cycle, you may notice these signs:

• Less discharge: Dogs in the estrus stage are no longer on their periods, so they will eventually stop bleeding altogether. 
• Friendliness or flirtatious behavior with male dogs: Dogs may lift their tails to get male attention and show male dogs that she is fertile and ready for mating.¹
• Increased vocalization: Dogs in heat may become more vocal to try to get attention, including moaning, whining, and crying. 
• Increased urination: Female dogs may urinate more often as a way to attract a mate because their urine contains pheromones. They may also urinate in front of males and lift their leg to urinate. Frequent urination could also indicate a more serious health issue, so you can maintain your dog’s urinary health by taking them to the vet regularly to ensure their urination is part of their heat cycle. 
• Mounting and humping: Mounting and humping are common signs a female dog is ready to mate. However, female dogs in estrus may hump anything, including their owners, male or female dogs, and objects. 
• Nervousness: Dogs in heat or those that are already pregnant may begin nesting by gathering comfortable bedding for their soon-to-be puppies. Dogs that aren’t pregnant may exhibit this behavior as a way to prepare. 

Prep For Going Into Heat

Female dogs in heat can get pregnant, so if you’re trying to avoid unwanted pregnancy, you’ll need to pay closer attention to your dog during this time. Since dogs naturally want to breed during their heat cycle, they may become more irritable or nervous. Additionally, they’ll require different types of care throughout the different stages of their cycle. Here are a few ways you can prepare for going into heat. 

Blankets and dog pads

During the first stage of dog heat, your dog will want to be comfortable. Additionally, since they’re going to experience discharge, you should invest in doggy diapers and wipes to keep them clean. Some dogs may want more attention during this time, so they’ll crawl up on the couch to snuggle up close with you. However, other dogs may want less attention than they normally get. Whichever your dog prefers, give them what they want; if your dog wants space, give it to them to allow them to take care of themselves during the heat cycle. You can also create a safe space for your dog where they can rest during the day to get away from the regular hustle and bustle of the home. 

Depending on how your dog feels during this time, you may also choose to bathe your dog to help them feel more comfortable and clean. 

Water, food, tracker

Your dog’s nutrition is especially important during this time. Your dog will need access to water and food to ensure their health and comfort during this time. Depending on your dog, they may become more tired, so keeping their food and water bowls near them will entice them to eat and drink. Additionally, you can start a tracker to mark how long the heat cycle lasts, allowing you to set a reminder for another six months to help you prepare. 

Of course, depending on your dog, they might go into heat more or less often. If your dog is experiencing their first heat cycle, continue to track everything to help give you a better idea for next time. While cycles can be inconsistent for the first few years, tracking your dog’s cycle and behaviors can help you understand what you need to do better for next time. 

Monitor them

Since dogs want to mate during their heat cycle, you’ll have to monitor them more closely during this time. Female dogs will actively seek a mate, so well-behaved dogs may be more prone to run out of the yard. If possible, consider keeping your dog in a secured enclosure like a crate or using a leash outside to ensure they won’t run away to find a mate. You should also keep any unneutered male dogs away from your pet if you’re trying to avoid pregnancy. 

Monitoring your pet throughout their heat cycle can also help you catch any irregularities that you can discuss with your vet. 

Go on walks

Female dogs in heat may need to urinate more frequently, and they may have nervous energy. Taking your dog on frequent walks can help burn off some of their energy while ensuring they have enough opportunities to relieve themselves. Of course, always keep your dog on a leash during their heat cycle to prevent them from running off to find a mate. You should also keep her away from other dogs on walks. 

Also, avoid taking your dog on walks if she’s tired. Dogs in heat are experiencing hormonal changes that can make them feel more lethargic than usual. If your dog is tired, it’s best to let her rest. 

What To Do After Heat

Once your dog has gotten past the estrus cycle and is no longer fertile, they’ll slowly start to return to their normal behaviors. If your dog is pregnant, they’ll need to see a vet as soon as possible to ensure their health and the health of their puppies. 

If you don’t want your dog to get pregnant, consider spaying her to ensure she won’t experience the heat cycle. Of course, you may choose to have your dog spayed at any point after that if you decide you don’t want her getting pregnant. 

If you plan to breed your dog but are waiting, keep your dog away from male dogs during their first few cycles. You can also begin preparing for the next heat now that you have a better understanding of what your dog will act like. For example, if your dog becomes more affectionate, you can plan to spend more time with them. Additionally, if your dog becomes more hyperactive, you can invest in a different method of keeping them in the yard during their next heat cycle. 

Caring For Your Pup

Once dogs begin their first heat, they’ll experience the heat cycle for the rest of their lives. However, learning everything you can about your dog’s heat cycle, including how they behave during the different stages, can help you make them more comfortable during this time. For example, dogs in heat may become more nervous or anxious, while others require more affection. 

Need help caring for your dog while she’s in heat? Talk to a Dutch vet. Dutch vets are available any time of day to answer your questions about caring for your female dog, whether she’s in heat, pregnant, or you want to avoid unwanted pregnancies.