Share a SolutionAsk a Question
To Top

How Long is a Dog in Heat?

If your female dog still has her reproductive organs she will go through phases of fertility. This guide is about how long is a dog in heat?


Share on ThriftyFunThis guide contains the following solutions. Have something to add? Please share your solution!

0 found this helpful
September 10, 2013 Flag

The canine estrus cycle is divided into four stages: proestrus, estrus, diestrus, and anestrus. Although the first three stages of the cycle are referred to as active heat, the period during the cycle when a non-spayed female dog is receptive to breeding and capable of getting pregnant (in season) usually only lasts from 18 to 21 days. Males will travel several miles to get to a female in season, so to avoid unintended litters, you must be extra vigilant in keeping her away from intact males during this period.


Proestrus (3 to 17 days): This first stage of the heat cycle lasts an average of nine days. The female will emit an odor (pheromones) that attracts males, but in this first stage of the cycle she will reject their advances by jumping, snapping, and growling at any interested males. Physically, you may notice a slight bloody discharge and a notable swelling of her vulva. A few days before estrus begins the bitch may let a male mount her, but she wont stand for breeding. Proestrus ends as soon as she is receptive to the male.

Estrus (7-9 days): The second phase of the heat cycle is called estrus, or standing heat. This is when the female is willing to accept a male for breeding. During this time the discharge changes to a light pink or straw color and the female will often lift her pelvis and raise her tail to the side to signal her readiness to breed. Because she can get pregnant during this time, keeping her safely away from intact male dogs is critical. Estrus lasts an average from seven to nine days (the range is 2 to 20 days) and ends when the female once again refuses to stand for the male.

Diestrus (60-90 days): This final stage in the active part of the cycle begins when the female refuses to stand for breeding. Most males lose interest now, too. The discharge may become redder for a few days before stopping completely and the vulva slowly returns to its normal size. When the discharge and swelling have ended, the heat cycle is considered complete. Diestrus lasts about 60 days, and then merges with anestrus. If the female was allowed to become pregnant during estrus, diestrus lasts until the she gives birth, approximately 63 days after conception.

Anestrus (130-150 days): The fourth and final phase of the estrous cycle consists of little to no ovarian activity. This is the time between the end of one heat cycle and the beginning of a new heat cycle. The length of anestrus varies, lasting on average 130 to 150 days.

Facts about the canine heat cycle:

Females dogs (bitches) become sexually mature when they have their first heat period. This usually occurs between 6 and 12 months of age, although there can be considerable variation among individual dogs and breeds. Toy breeds become sexually mature several months earlier than giant breeds. Sexual maturity does not correspond to physical maturityachieving an adult height and weightwhich generally happens at about 14 months of age in medium-sized dogs.

Ovarian activity and the ability to conceive begin to decline after 6 years of age and ceases (in most females) at around 10 years of age.

Most female dogs will come into heat twice a year until they are spayed. Some may come into heat every five to nine months. Basenjis are noted for only having only one heat per year. The heat cycle is specific for each individual and not influenced by external factors such as hours of daylight. Many females have their first heat cycle at approximately the same age as their mother did.

Although a female dog may be able to physically conceive as young as 6 months, she should not be bred until she is at least 2 years old. There are two reasons for this: 1) a young dog is not yet emotionally mature enough to deal with a litter, which may cause her to harm or abandon her puppies and 2) the common tests used to screen for health abnormalities prior to breeding (hips, elbows, heart, eyes) will not provide accurate results until she is 2 years old.

Some dogs heat cycles get messy, while others are hardly noticeable. Doggie diapers and are available to protect your house, and you may also want to clean her vulva area once or twice a day with a damp cloth to prevent skin irritation. Be prepare for some behavioral changes, too. Your your dog may appear tired, cranky, agitated, attempt to mount other dogs, or try to escape and breed.

Source: Dog Owner's Home Veterinary Handbook, Fourth Edition; The Merck Veterinary Manual, Seventh Edition; Personal Experience.

CommentWas this helpful?Helpful? Yes
March 16, 20150 found this helpful

Or if you are concerned about complications with anesthesia/surgery, don't want to cause hormonally-related medical problems (of which there are more involved with spaying than with not), and you think you have it in you to be responsible enough to not allow your pet outside unattended during her heat cycle (and/or to keep close tabs on your males), then you can help control the pet population without putting your animal through unnecessary, elective surgery.

But, if you got a dog to release into the backyard to bark at your neighbors while you surf different forms of media, by all means spay/neuter your pet. The surgery's a risk you'll just have to take as a result of your unwillingness to be vigilant.

Most people aren't...thus the s/n mantra recited at all of us like religious dogma (pun intended) every time we take three steps... like Dorothy being inanely reminded over and over again to follow the %@#! yellow-brick road!

Related Content(article continues below)
ReplyWas this helpful?Helpful? Yes
Read More Comments


Ask a QuestionHere are the questions asked by community members. Read on to see the answers provided by the ThriftyFun community or ask a new question.

0 found this helpful
March 1, 2011

How long will a dog be in heat? I'm very new at this.

By Annette from Ontario, Canada

Answer Was this helpful? Yes
March 1, 20110 found this helpful
Best Answer

Usually about three week or 21 days. It is the second week you really need to watch your dog as she can link up with a partner. The third week she is waning down and can still be linking up, but interest is dissipating. The full 21 days you need to keep your female from being alone outdoors as other male dogs will come around; you'd be surprised at how many dogs will appear at this time and dog fights can happen and maybe harm your female. When the female's tail moves toward the side; she's ready for mating. If your dog is going through her very first heat, do not allow her to get hooked up. She isn't ready or fully matured for it yet and can cause harm to her or a litter. Wait at least for the second heat usually five months after the first heat. Then if you want her to have a litter it's safe. A good breeder does not allow their female dog to have litters at each heat, but alternates to every other one. This is hard on the dog otherwise and creates a lot of complications unnecessarily for the dog and the pups. There are panties made just for the female in heat that you insert a sanitary pad inside and keeps things clean if she's in the house.

ReplyWas this helpful?Helpful? Yes
March 2, 20110 found this helpful

Thanks to Bell & Summers mom for posting the info about Luvs size 6... I have a lab mix and she is a BIG dog! I had to modify the diaper by cutting a tail hole, but it worked like a charm! I put them on tape side up (backwards) because it's easier.

ReplyWas this helpful?Helpful? Yes
March 2, 20110 found this helpful

Talk to your veterinarian about having your female de-sexed unless you are a registered licensed breeder. Good luck.

ReplyWas this helpful?Helpful? Yes
March 3, 20110 found this helpful

Please have her spay, there are too many cats/dogs that are in the shelter every day that are put to sleep.

ReplyWas this helpful?Helpful? Yes
March 3, 20110 found this helpful

As everyone else has said, a dog is in heat for at least 3 weeks and can get pregnant during any time of the heat cycle. But, please, why do we keep seeing these posts. Why don't you folks have your dogs spayed and/or neutered. There are so many, many dogs in shelters, being kept in cages, being killed, because there are too many unwanted dogs in these countries and you want to add to that! Why, why, why.

ReplyWas this helpful?Helpful? Yes
Anonymous Flag
September 26, 20120 found this helpful

There are many reasons why someone would wait to spay or neuter their dog or cat. As long as they are responsible and do not allow their pet to mate, then it should not be an issue until the owner finds the right time to alter.

For us, we need the hormones of my dog's uterus for proper bone and mental growth for what her job is. I also want to wait because OFA testing usually happens at 2 years and I only want her sedated once. I will spay three months after her last heat closest to her second whelp day.

There has been research and documentation against pediatric altering.

Studies have shown more instances of joint damage in larger breed dogs with those that were altered before adolescence. Waiting until adulthood increases your chances of healthy bone and joint growth. Usually with cats there is not a reason to wait, but I will right up until he/she starts going into puberty, about 4 to 5 months.

I am all for altering, especially if you are unable to make sure your dog will not breed while waiting for the right time, but I did want to say that there are reasons why someone would wait to spay or neuter their dog.

ReplyWas this helpful?Helpful? Yes
November 18, 20160 found this helpful

I know and I feel so guilty for not spading my dog when I see all these dogs on the strs. Multipling its so sad but after she gets over her first heat I will get her spaded

ReplyWas this helpful?Helpful? Yes

0 found this helpful
April 2, 2015 Flag

My 16 month old Whippet just had her first season. It's been 4 weeks now. Is there something wrong?

By Jacqui

AnswerWas this helpful?Helpful? Yes
April 8, 20150 found this helpful

It should be no longer than 4 weeks.

ReplyWas this helpful?Helpful? Yes

0 found this helpful
June 27, 2011 Flag

How long will dogs be in heat?

By Aryana from CA

AnswerWas this helpful?Helpful? Yes
June 28, 20110 found this helpful

I think a week to ten days. She'll come into heat and then she's interested but wont let dogs approach her. Then later she'll go into standing heat and that's when she will let dogs approach. Call your vet, they should be able to tell you. Small dogs might be in heat a shorter time period, though, I'm not sure.

ReplyWas this helpful?Helpful? Yes
June 28, 20110 found this helpful

Our dog Mazzy seems to be in heat for at least two weeks, aftetrwards, in about the 60 some days after (when puppies would've been born) she chooses several of her toys as her babies and cares for them just like they were really puppies! We plan to have her spayed because the whole thing is just too heart wrenching!

ReplyWas this helpful?Helpful? Yes
June 29, 20110 found this helpful

The only people qualfied to answer this question is your Veterinarian or registered breeder. Remember bitches can have phantom pregnancy. Talk to these two people for the correct information

ReplyWas this helpful?Helpful? Yes
June 30, 20110 found this helpful


Are you a breeder? If not, you can have her spay.

ReplyWas this helpful?Helpful? Yes

0 found this helpful
January 7, 2010 Flag

We recently got a new puppy. She about 8 months old now and she got her first period on Dec 5th. It's been a month now and she is still spotting. Her vulva is still enlarged which I'm assuming will shrink once her cycle completes. She has Renal Dysplasia so I don't know if that is contributing to a long cycle. I'm wondering when her spotting is going to stop. Any help would be great.

By Todd from Phoenix, AZ

AnswerWas this helpful?Helpful? Yes
January 7, 20100 found this helpful

21 days is the normal heat cycle. Once the bleeding ends around seven to ten days; a female can begin to mate and in the third week is the waning down time. If your dog has gone past this time period and is still passing blood, I would suggest a vet visit would be in order.

ReplyWas this helpful?Helpful? Yes
January 11, 20100 found this helpful

What a beautiful little girl! Since she has Renal Dysplasia, please take her to the vet and don't depend on well-meaning advice from us amateurs. There may or may not be a problem and the vet is the only one who can say for sure. He'll also be able to tell you more about what to expect with her heat cycle.

ReplyWas this helpful?Helpful? Yes
January 12, 20100 found this helpful

All pets should be spayed or neutered. It's healthier for the pet, and less stressful for you having to worry about these things. :-)

ReplyWas this helpful?Helpful? Yes

0 found this helpful
March 2, 2015 Flag

How long is a dog in heat?

By Christine

AnswerWas this helpful?Helpful? Yes
Pets Dogs AdviceJune 25, 2013
An orange cat in heat.
How Often Can a Cat be in Heat?
Hot coffee mug on wood table.
Removing Heat Marks from Furniture
Watering Flowers
Helping Your Garden Beat The Heat
Above Ground  Swimming Pool
Saving Energy on Swimming Pools
Mother's Day Ideas!
Easter Ideas!
Ask a Question
Share a Post
You are viewing the desktop version of this page: View Mobile Site.
© 1997-2017 by Cumuli, Inc. All Rights Reserved. Published by . Page generated on March 28, 2017 at 2:29:38 AM on in 4 seconds. Use of this web site constitutes acceptance of ThriftyFun's Disclaimer and Privacy Policy. If you have any problems or suggestions feel free to Contact Us.
Loading Something Awesome!