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The 4 Stages of the Dog Heat Cycle (Signs Your Dog Is In Heat)

dog heat cycle

Summary: We review the 4 stages of the dog heat cycle. Part of this article discusses the signs of heat you should be watching for to tell if your dog is in heat. Don’t stress about unwanted pregnancies, know what to do if you are not going to have your dog spayed.

What are the Signs of a Dog in Heat?

One of the problems that many dog owners face is preventing unwanted pregnancy. If you own a male (also called a Sire), you may never know where your dog has sewn his wild oats. If you have a female (also called a Bitch), you will certainly know about the pregnancy, especially when you suddenly find several puppies hiding under their mom’s fur. While the responsibility to prevent improper pregnancy lies with owners of all dogs, it seems the majority of the work is on the part of the bitch’s owners.

To prevent (or encourage) pregnancy, its important to know when your dog can become pregnant. Your dog can get pregnant during her heat cycle (or estrus). Dogs DO NOT go through menopause the way humans do. As they grow older they are less fertile, but it is possible for your older dog to become pregnant. Dogs typically have two heats per year. Each dog differs in length of heat, discharge amount, messiness, and personality changes. Watch your dog and learn her cycle. If you are a professional breeder, or someone considering breeding your dog, you should wait until your dog is in her third heat before breeding. She should be vet checked and up-to-date on her shots. Choose her mate carefully, focusing on improving your chosen breed. Request that he is vet checked and up-to-date on his shots as well.

Four stages of the Dog Heat Cycle

  1. Proestrus
  2. Estrus
  3. Diestrus
  4. Anestrus

Your dog is not fertile during the first days of proestrus. But keep in mind that male sperm can live for several days. It’s important to watch her closely and consider buying some diapers or pants to protect her from mating with unwanted suitors. This can compromise your dog’s health and the genetics of the puppies. There are several types of dog diapers and pants available. OR you can get creative, and make some yourself. Using a dog diaper can prevent the staining of carpet and furniture. Dog diapers also can mean a lot less cleanup for you. There are several types of dog diapers to choose from. There are disposable and reusable (washable) dog diapers. Each one has benefits of its own.

Some pet owners prefer to use disposable just for their convenience. Reusable dog diapers come in assorted fabrics, colors and patterns. Pet Parents makes a washable dog diaper available at Amazon that comes in a 3 pack. It has 3 different sizes (small, medium, and large). This product works very well for the intended purpose and is even listed as ‘Useful for female dogs in heat.’

Washable Dog Diapers (3 pack) from Amazon

If you prefer a disposable dog diaper for controlling your dog’s heat cycle, then try the Simple Solution Disposable Diapers for Dogs. These disposable dog diapers come in 5 sizes from x-small to x-large.

Simple Solution Disposable Dog Diapers from Amazon – Pack of 12

It’s important to know when your dog is coming into heat and going out of heat. There are some clear signs and some subtle clues. Pay attention to your dog and learn her behavior. This will help you understand what’s going on when she ‘does’ come into heat.

Proestrus Stage

This stage of dog heat can last from 4-20 days. The average is 7-10 days. There are 3 common signs for a dog in heat during this stage:

  1. Swollen Vulva: This is one of the best ways to spot the beginning of a dog heat cycle. The swelling is a significant difference over her normal appearance. Her teats may also swell slightly, but this is not a great heat indicator and can be tricky to spot.
  2. Discharge: Your female may suddenly spend a lot of time licking herself. Take a tissue and wipe her vulva. If you notice red discharge, and her vulva is swollen, that’s a pretty good indicator that your dog is definitely coming into heat. It’s important to check this, since timing is everything when it comes to mating (or preventing a mating) your dog. The first day you notice the bloody discharge is called “DAY 1”. Mark it on your calendar.
  3. Suitors: The third sign of heat is not found on your dog, but in the presence of other dogs. You may notice neighbor dogs hanging out around your house. They can smell your female’s heat cycle. You may notice that your dog will tuck her tail often, protecting herself. She is not ready to accept a sire.

Estrus Stage

The Estrus Stage of the Dog Heat Cycle typically last from 5-14 days. The time your dog is fertile (her actual heat). At this stage, the discharge typically changes from red to straw colored. In many dogs, it’s still somewhat pink, but you will notice a definite difference in color from the beginning of proestrus. This change usually occurs around day 8 or 9. Your dog will also be willing to accept a sire during this stage. She will switch her tail to the side. She may whimper and try to be outside more often than is normal for her. She is following her instinct to breed. Keep a close eye on her. Even if she is in a kennel, she can still end up pregnant.

Dogs get VERY creative during this stage. If you notice strange males in your yard, stay away from them. Bring your dog inside and wait for them to leave. When males are anxious to breed, they can be much more likely to bite. Don’t take your female to the pet store or the dog park. You can inadvertently cause problems that you really don’t want. It’s best just to keep her secluded to your yard and home. We have even seen a male sire impregnate a bitch through the holes in a chain link fence – so be very protective and cautious. Otherwise, you are going to be ordering DNA testing kits. To determine the dog’s due date, use our Dog Pregnancy Calendar Calculator.

Diestrus Stage

The Diestrus Stage of the Dog Heat Cycle usually begins around day 24. This stage can last from 60-90 days. Your dog is no longer fertile at this point. Her discharge will change from straw colored to red and then stop completely. She still has a scent and can still attract unwanted attention, so wait until she has completely stopped bleeding before venturing into public places.

Anestrus Stage

This is the fourth and final stage of the dog heat cycle when your dog is normal. This stage last about 60-90 days, at the end of which, the entire heat cycle starts again.

In conclusion, pay attention to your dog. Watch her dog heat signs. Know where she is at all times to prevent unwanted suitors from mating with your dog. Have her vet checked and be sure that you are willing to go through all the work necessary to raise puppies BEFORE breeding her. If you have a male dog and have no interest in using him as a stud dog, please consider neutering.

If you have further comments or questions about ‘The 4 Stages of the Dog Heat Cycle’, feel free to visit our Forums, Use our ‘Ask a Breeder a Question Link’ or make a Comment on this article below.

Photo by istolethetv


  • my male dog has become disinterested in my bitch could he have already done the deed do they lose interest once they have mated with bitch

    • I have a white/brown/black ear Shih-tzu girl and a black boy. I was wondering what puppies I could expect if I mated these two? would they all be black or could I expect some white/brown ones?

      As this is her first heat cycle I don’t want her to get covered so I keep her in her diapers. Is there anyway to make this process more hygienic or at least less harmful to her? I have a human pad in there for heavy flow so if she does have a whoops in there it will absorb it, but I don’t think it is absorbent enough. Could I put in some baby powder to absorb some more of the wetness? Should I maybe try baby diapers and fashion something that would absorb more pee so she can stay dry and relatively comfortable? I take her out of the diaper and let her run free at night while i watch her and the bf keeps the boy company. I have to leave her and her boyfriend at home and sometimes they are alone, and I don’t want to keep them apart if it means they get lonely, but I don’t want either of them to get hurt and I definitely don’t want my 7 month old baby to have babies. She’s so small still!

      I’m of two minds to have my boy sterilized as I can always have my baby covered by another Shih-tzu I know of, but I might want to have puppies with him at least once… Then what is more traumatic, to leave him as he is and experience his first female in heat (he’s bout 10 months old) with all the hormonal and emotional upheaval that leads to (not to mention the peeing against everything problem) or to take him to my parents and have him stay there for 2 weeks or to just have him neutered. Any advice would be helpful as I try to make up my mind about this.

  • I found this article very informative. Although I am still very concerned about my female shi tzu. She is only 8 1/2 months old and this is her first heat. My male is 3 years old. We intend to breed them but of course wanted to wait until her second or third heat. We have done a great job in keeping them apart until yesterday which according to my calendar is day 19 of her heat cycle. We left them alone for just a few minutes and then found them tied. We squirted them with the hose and they pulled apart immediately. After that our male showed no signs of wanting to mount her. But again today, day 20, we found them tied again. This time it took longer for them to get apart. We so not want her to be pregnant. I am confident I am correct on the days I have recorded on her heat cycle. Does anyone know if I am likely to have a pregnant dog or are we safe until next time?

    • You should expect puppies in about 63 days from the first day that they tied. If she allowed him to tie with her, chances are she is receptive. Take her to the vet and see if they can tell you whether she is bred or not. Start her on prenatal vitamins asap just in case. Good luck!

      S Seay

    • My pug is in heat and she stays in heat for at least 26 days. We are on day 22 and my male is still going crazy. Last heat she got pregnant on day 21. They are all different. It’s a pain keeping her locked away in the kitchen for a month. I have baby gates all over my house. Best way to keep them apart. Just make sure you get the tall gates. I have a little dachshund that can jump the shorter ones.

  • can someone please tell.. would a male dog stop trying to mate my female if he has already done the deed.. if not
    could you explain to me how he lost interest all together.. when for a full week he would not leave her alone ?

    • As a general rule the male will continue to brred with the female as long as she’s willing to accept. The only thing I can think of that would stop a male’s interest is the female going out. You may have bred they late in her cycle. Also some male have low testosterone levels that affect their drive.

  • This is my female mini-dachshund’s fourth heat cycle. We have had a stud lined up for her for months. When she finally went into her heat cycle, we waited until her 14th day to breed. My bitch was very receptive and they tied for about 20 minutes. It has been 5 days since and I noticed she still has some discharge coming from her vulva. It is mostly clear with a tinge of pink. Does this mean it did not take or is this a normal part of the process?

  • My great dane is about 10 months old and she has never gone into a heat cycle. I read that it can be as long as 14 months..but I’m still worried. Her mom had plenty of heats as young as 6 months. Should I be worried? Is this normal?

  • ShihTzuLuvr
    Article very appreciated. My 11 mth Shih Tzu in now in her second week of heat cycle. I have an 8yr old Shih Tzu male also. I have kept them apart for the most part. One more week to go. But the constant whimpering from her and barking from him is driving me crazy.

    • I take my bitch to an outside stud, and these are just a few things I have learned the hard way…
      I have a male and female schnauzer that are brother and sister. When I purchased them, I had no intention to breed. When my female goes in heat, my male begins to go crazy about day 13 and it lasts through day 18, roughly. I have been told to keep them apart, and that was a big mistake on my part. My male does the bark thing and yes it does drive you crazy! I have found that if I put them in their crates, side by side, he is content, and she is happy to be left alone. I also use a baby gate and divide territory. I find that as long as he can lay by the gate and at least see her, he is happy. I do think that you have to find what works best for your dogs. If you are breeding the two, let them be together as long as you are present. She will deter him when she isn’t ready, and if she is ready then she will be accepting and flag him. Once he “has” her he will generally relax for a while.

      • When my female comes into heat (we are having her spayed after she is 2 years old) my neighbors dog goes crazy. He barks and whines and is so annoying. We have tried talking to our neighbor, they said we need to keep our dog inside (which we do) and that he will stop. Is there anything I can do to help him to calm down or do I just have to deal with it?

        I keep my dog with me at all times. We are mostly indoors and she does wear a diaper. I don’t take her to the park OR on walks when she is in heat. I don’t want other dogs following me home. I am planning on spaying my girl, but I want to make sure she is old enough to have the procedure.

        Any advice???

        • The best thing to do is spay your dog. If your going to spay her any way she doesn’t need to be a certian age before she has surgery. Especially if you have a large breed dog getting her Spay done sooner will cost you less. A healthy dog of any breed can be spayed after her Rabies Vaccine without it having any effect on her personality or some people worry about there dog getting enough “hormones” I’m Registered Veterinary Technician and by spaying your pet before she goes into her first heat cycle is recc. She is at less risk of cancer as well as an infection in her uterus wich with every heat she has she is at risk. Unless otherwise directed by your Veterinarian. If your worried about her size if she is a very small breed. Find a Veterinarian that monitors with pulse ox/ ekg, bloodpressure, etc. Find what methods they use for induction ( putting her under anesthesia ) ask if they do bloodwork. see what the procedures are for recovery. If its financial they have programs that offer lowcost or no cost spaying/ nuetering. check at your local shelters they usually offer low cost spays. Also every year they have national spay day check with the aspca or on the website to find out when its happening to get your voucher.

          • I am not a breeder, but I have 3 Chihuahuas, 1 male, 14 yrs., 2 females, one 8 years, one 4 years. The youngest female has not been spayed yet. Both females are retired breeders. I won a voucher for discount spaying, so found out when and took my oldest female that morning. There must have been 50 dogs there, each in a carrier. They loaded them into pickup trucks and vans and off they went. No one knew where! That evening, they brought them back to the same parking lot at the local APL. They told all of us that each of our dogs had been given a shot for pain and they shouldn’t need anything else. I got her home and she was miserable. I called my vet and asked what I could give her. Half a baby aspirin. It helped. However, as she was healing, I noticed that there was black suture working out of the incision. Took her to the vet. He pulled about 2 inches out and snipped it off. Over the next several weeks, more continued to work out through the length of the incision. About 3 weeks after the surgery, I went to pick her up, and she yelped when I put pressure on her stomach. It has been about a year since the surgery and she still gets sudden, stabbing pains in that area and she still yips at times when I pick her up. My thoughts about low cost/no cost spaying or neutering is this: Save up your money and take your dog to a reputable vet. These people gave us no phone number for emergency or questions. And please explain how 3 or 4 vets managed to do surgery on 50+ dogs in 6 to 7 hours? Talk about a “mill”. My youngest is in heat right now, but will be going in for her spaying when she is done. I will pay the vet to do it. It’s the least I can do for a loving, dependent and trusting piece of my heart. Please, don’t support the spaying “mills”!!!!!

          • AZDudette- got some rough news for you girl. No doubt the docs could zip through that many pups in a short amount of time, but at what cost?!

            Chances are you pup is suffering from fissures and internal scarring due to the haphazard way the “doc” did the operation. These scars are caused by the rushing and not-so-gentle care of the internal organs by the surgeon. Pretty much they will just push and shove the organs around and not take care to ensure there is little to no trauma to the tissues. You wind up with scar tissue that branches out like a spiderweb (way it was described to me) and when that web is stretched it pulls everything it’s attached to. The example I was given was to tie 4 apples to 4 different strings, then connect those strings to a fish hook….then run that fish hook through your belly button and drop the apples! May be a tad dramatic but you get the gist of the example.

            There is a corrective operation that will clean up the area, but you need to move on it pretty quickly while the scars are still fresh and haven’t hardened so much. It really sucks that your pup will have to go through another operation but consider a Chihuahua will live almost 20 years in some cases, but at least 12-15. The rest of her life she will have that tugging on her belly and when she gets older it will be exacerbated greatly due to a loss of muscle strength that would help hold her abdomen somewhat tight or rigid normally.

            Really hate to hear this, but check with your local pet hospital to see about the fix, sooner rather than later.


            2 Huskies…she’s in charge but let’s him and me think we are!

  • Your article was very informative. We have an American Bulldog female, 2 years old, 3rd heat we are trying to have bred. She has never been bred before. We have taken her for progesterone blood assays 4 times and her level on the 1st assay was 1.28 nanograms (2nd day of heat); 2nd assay was 1.57 ng (day 5); 3rd test was 7.08 nanograms (day 11); 4th test was 22.03 ng (day 13). This was the spike they were looking for (more than 10 ng in 2 days). She still would not accept a male.. we tried again on day 14 – no luck. We tried again on day 16 – still no luck. Our females discharge has gone from bright red to dark red and now is back to bright red again as of today – day 16.

    Her mother bred on day 18 & 19, do they sometimes follow the same pattern with breeding habits? Any suggestions would be appreciated.

  • In humans the first day of the menstrual cycle is the first day of a women’s period. It varies from 2-3 days to say 7-8 days. A women ovulates and 12-14 days later she starts her cycle (period) over again. Whether it be a 28 day cycle or 35 day cycle. I’m really confused by your math when a bitch comes into heat twice a year. Is that every six months or 90 days when you stated it starts over again?

  • I have a female Golden Retreiver/Great Pryenees Mix Puppy(Golden Pryenees is the “hybrid” name) that is almost 8months old, hasn’t had a heat cycle as of yet and a 4month old female black lab puppy. My Golden Mix is approx 60-70 pounds, my vet recommends wait until she’s 9months due to her breed mixture… My vet doesn’t charge extra for if she goes into heat before the 9month old mark… However… I need to figure out when to expect her to go into heat so I can keep her inside the apartment and away from the dog park(our fav haunt that their dog walker and myself take them to on a daily basis), and when to expect my Lab to go into heat as well. Any suggestions/help?? I do have baby diapers on hand thanks to having a 1 yr old, lol.

    Proud Mama of 2 little girls and 2 female furbabies. 1 Golden retreiver/Great pryenees mix and 1 Black Lab.

  • My 1 year old miniature schnauzer is in heat for almost 2 weeks now. When is it advisable to bring her for walk in the park?

  • My 13 month old German Shepherd went into her 2nd heat on 7/12/12. We adopted her on 7/7/12 and don’t know anything about her first heat. Her discharge changed on 7/28/12. How long generally are the still fertile? I see anywhere from 5-14 days what is everyone elses experiences? The discharge will change from straw-pink back to darker blood once they aren’t fertile? Am I correct? We have an intact male we are planning on breeding with but want to wait for at least another cycle. We have had her boarded since 7/18/12 and want to bring her home ASAP but don’t want puppies!

  • If someone could please answer my questions I would be so thankful.
    My female has spotted for about a week but not exactly sure and 3 days ago she tied with my male. She still seems receptive, but my male seems uninterested!? He will mount her, but will just stand there without thrusting and then gets right off. He still licks her and smells her and smells her urine and constantly marking his territory outside. Her bleeding has increased tonight and is a bright red (it was lighter before). Her vulva had only swelled up a few days before they mated. Could she have just accepted him too early? Or could she be going out of heat already? Is the swelling suppose to go down before she accepts a male or should the bleeding stop before they mate? This is her 2nd time breeding and last time the male tied with her everyday since she would accept him until she went out of heat (it was a different male) so this is why Im so confused! Ive even been separating them during the day because thats what I was told to do. Can someone please help me out? Thanks in advance!

  • I accepted a 7 yr old non-spayed female dog into my home last week. Now she is in heat. I have always fixed my dogs at an early age. I just read about the 4 stages of the heat cycle and worry that this dog could be in the Diestrus stage. She has been showing interest in the male dogs from day 1. She has had swollen genitals. Today she is having red discharge. Is she in the Proestrus or Diestrus stage. Could she have “hooked up” before coming to my home? I was going to get her fixed, but she did not give me the chance.