Does A Dog Have to Be On Heat to Get Pregnant? [Dog Heat Explained]

Are you worried your dog is pregnant?

Or do you want to breed your dog and are worried about its safety?

Or maybe you adopted a female pup recently and were simply curious about possible precautions you need to take.

Whatever the reason may be, you want to know whether your dog can get pregnant in heat. 

does a dog have to be on heat to get pregnant
Does a dog have to be on heat to get pregnant? Heat cycles and dog pregnancy explained

Well, you’ve come to the right place! We’ll answer all your questions and more. But let’s first start with the main question.

Does My Dog Have to Be in Heat to Get Pregnant?


Your dog can only get pregnant during its heat cycle. It is, therefore, necessary to know when your dog is in heat. 

But how can you know?

Keep an eye on the signs and it won’t be too difficult to keep track of your dog’s heat cycle.

What Is Heat? 

In heat, season, or estrus cycle. If all these terms have left you confused, don’t worry, they all mean the same. An estrus cycle is the reproductive cycle of female dogs. 

The cycles begin once the dog has reached puberty or has become sexually mature. However, the age at which a dog reaches maturity can vary for different breeds. Smaller dog breeds may reach maturity after 6 months, while bigger dog breeds tend to become mature at 18 to 24 months of age.

These cycles are often irregular during the initial years and get adjusted as time passes. Once regular, the cycles occur twice or thrice a year. The number of cycles your dog has will also depend on its breed.

It is also important to remember that different dog breeds have different reproductive cycles. Smaller dogs mature earlier than bigger dogs, the cycles last for different periods, and the number of cycles in a year keeps changing. It is best to focus on the breed when looking for more detailed information.

Is My Dog in Heat?

Does A Dog Have to Be On Heat to Get Pregnant? [Dog Heat Explained] 1

Below are some signs that are common to dogs during the heat cycle. These signs are not the norm though. They may or may not show up, and your dog could look completely normal to you while in heat.

Many dog owners fail to observe the subtle signs. Some do not find out about their dog’s pregnancy until their dog is in the last stages of pregnancy, only to be surprised with a litter (however cute they may be). If you are not careful and do not plan, litter is not easy to handle. Here are the common signs to watch out for:

  • Pink or bloody discharge
  • Swollen nipples or vulva
  • Interest from male dogs in the neighborhood
  • Tail flagging, raised tail, or tail tucking
  • Frequently passing small quantities of urine
  • Lacking focus
  • Ears up
  • Licking the whole body or the rear end
  • Mood changes

However, these signs may not be related to the heat cycle specifically. If anything worries you, then it is best to consult your vet. 

How Do I Take Care of My Dog in Heat?

Be extra careful while bathing your dog as her swollen body parts will be sensitive to the touch. 

Allow space for her mood swings. These are very specific to each dog so be careful not to get too disturbed. Your dog may wish to be alone for this period or they may stick around more often than normal. Or they could do both alternatively. This is only temporary and will pass as the cycle continues.

Their mating instinct will keep getting stronger during a heat cycle. If you see many dogs around your house, don’t be alarmed. They are attracted to hormones and pheromones. These are present in your dog’s urine and their purpose is to signal to male dogs that she is soon going to be ready to mate. However, if you don’t want a litter of puppies, it is best to not let your dog out of sight during this time.

What Goes on During the Dog Heat Cycle?

a mother dog and a puppy dog
A mother dog and a puppy sitting side by side

A female dog has four stages in its reproductive cycle, and the cycle can last 18 to 22 days. 

The four stages of dog heat are:

  • Proestrus
  • Estrus
  • Diestrus
  • Anestrus

Let’s take a look at the stages in detail.


The cycle begins when your dog starts to attract male attention. Her body parts will start to swell and there will be a bloody vaginal discharge. This stage lasts anywhere from 5 to 15 days. Even though the cycle has begun, your dog won’t be ready to mate until the next stage.


You know the estrus stage has begun when the vulva has become enlarged from swelling. The discharge will also have changed from bloody to pink or yellow. Your dog shows more receptivity to male attention. Your dog is most fertile in this stage and is ready to mate. This stage will last from 5 to 15 days.


Also known as the metestrus or luteal stage, this when mating is complete. All signs of heat disappear and everything looks normal. The discharge turns red, the vulva returns to its normal size, and your dog is no longer receptive to males.

If your dog doesn’t get pregnant, then this stage will last from 60 to 90 days. However, if your dog does get pregnant, then this stage lasts throughout the pregnancy until your dog has given birth. The duration of pregnancy, or gestation, is an average of 60 days from conception. 


Though not a part of the cycle, this stage refers to the time between the end of a cycle and the beginning of the next. You can finally relax during this period as your dog can’t mate. It lasts between two and three months.

If you do notice the cycle to be longer than three weeks, it is best to visit the vet. Also, try to look at all these signs as guidelines with which you try to gain a better understanding of your dog. Do not think of the list as a must-have, must-see checklist. Many factors should be taken into account when determining what stage your dog is in.

Some Facts to Note:

The duration of the cycle of dogs that have been bred before will vary.

Delivery or whelping occurs naturally for some breeds, while others need cesarean sections to help them deliver. If you have a small dog or a toy breed, then it is best to consult a veterinarian to ensure that the dog and the pups are safe throughout pregnancy.

Even though the sperm is released, the eggs may not be fertilized. This is completely normal. Eggs are fertile for 48 hours and sperms survive inside the vaginal tract for a few days. This means fertilization can take a day or two after mating.

Is My Dog Pregnant?

a puppy outdoors with a rope tug toy

You think your dog has been in heat for the past week, but you only recently noticed. 

Has there been a sudden increase in the number of dogs flocking to your house?

And you left your dog unsupervised yesterday . . .

If you relate to these situations and are worried that your dog may be pregnant, then look for the signs given below before you start to panic.

  • Nauseous or vomiting
  • Gaining weight
  • Eating more
  • Napping more often

The best option now is to schedule the earliest visit to a veterinarian to discuss your options.

What Happens То Му Dog During Pregnancy?

In the two months of pregnancy, you will notice certain changes in your dog. As the weeks progress, their bodies and behavior will change. You can visit the vet after the third week to check up on their condition. 

When the dog starts to milk, you will know that the day of delivery is closer. Keep a watch on your dog for the next few days and be available when the time finally arrives.

There is also the common cause of false pregnancy where a dog starts to believe she is pregnant. This starts after the second stage and can be extremely dangerous for the dog. During a false pregnancy, the dog’s body changes to prepare for a pregnancy that isn’t real. This causes hormonal imbalance that can sometimes result in death.

How Do I Take Care of My Pregnant Dog?

During pregnancy, make sure to give your dog good quality food at regular intervals. The dog may eat more but make sure she doesn’t eat too much food at once. Too much food can be heavy and uncomfortable for her belly and her pups. Double her food intake gradually as the pregnancy progresses.

Regular light exercise should be followed for the duration of her pregnancy.

Visit your veterinarian regularly to discuss her progress and monitor any harmful developments. 

Give your dog all the prescribed vaccinations on time to prevent any infection from being passed on to the puppies. 

You can also create a comfortable space for your dog to deliver, or prepare a box for whelping. 

The delivery space should be away from the busy movements of the family. Also keep plenty of towels, papers, and dispensable cloth handy to use when the pups are born.

During lactation, she will require thrice the normal amount of food. If she refuses to eat more, then try not to force her and instead feed her small amounts at intervals.

Is There A Right Age/Time to Breed Your Dog?

Yes. The best age to breed a dog is after its second heat cycle. This also depends on whether the dog has reached puberty at the age normal for its breed. 

A dog can be bred anytime from the first cycle till it reaches 7 years of age. However, pregnancies that occur later can be complicated and stressful for the dog and the pups. 

If you want a large litter, consult your veterinarian. It would be advisable to breed when the dog has matured as this is when they produce a greater number of pups. The litter size of an older dog is generally small.

Dogs, unlike humans, can conceive throughout their lifetime. Their reproductive cycles do not stop at a particular age. But these pregnancies, expected or unexpected, can be dangerous. This is the reason most vets will advise you against it.

How Do I Prevent My Dog from Becoming Pregnant?

You may not want to breed your dog and supervising them during heat cycles may seem too much of a hassle. In such a case, it is best to surgically sterilize your dog before her first heat cycle. The first estrous cycle usually occurs when your dog is 6 to 20 months old. It is possible to sterilize your dog once it is eight weeks old, but the vet will probably advise you to get the surgery done later on. Most dogs are spayed right before they become six months old.

What Is Spaying?

The process to surgically sterilize your dog is called ovariohysterectomy, also popularly known as spaying. It is a surgical procedure that removes the dog’s uterus and ovaries.

Why Should You Spay Your Dog?

Are you afraid of putting your dog through a sterilization surgery? Do you think you can protect your dog from getting pregnant by simply observing it during all of its heat cycles? If not, you may want to consider getting her spayed. 

Below are the pros and cons of spaying that may help you make the right decision.


  • Reduced health risks
  • Less mess in the house
  • Prevent unwanted pregnancies
  • No frequent urination
  • No need to supervise heat cycles
  • No male dogs visiting your house
  • No mood swings
  • Less expensive than pregnancy
  • Avoid death due to pregnancy
  • Control overpopulation of dogs


  • Surgical risk

  • Weight gain after surgery

  • Decrease in metabolism

  • Complications if spayed at the wrong time

  • Can’t be reversed

  • Changes in coat

  • Risk of urinary incontinence

  • Increased risk of hemangiosarcoma

Spaying or not spaying your dog is your decision and we hope the information given above can help you make the right decision. Discuss your living condition with your vet and come up with a plan that best suits your dog.

cockapoo puppy dog door
A Cockapoo puppy sits patiently near a front door.


While all this information is meant to help you out, it is necessary to consult a veterinarian for a more detailed understanding of your dog. The vet will also be able to look at your dog and give you advice that is particularly applicable to your dog’s breed. 

Regardless of the conditions under which your dog becomes pregnant, it is necessary to take proper care of her and ensure the heat cycles and pregnancy are safe and successful. 

You may even find yourself pleasantly surprised when one day a litter of cute pups makes its way into your life.