Your Dog In Heat

dog in heat

Your female dog will be in heat for about three to four weeks, once or twice a year. The dog heat cycle begins when your pup starts releasing the hormones that enable her to become ready for mating. Mating hormones will make your female dog more appealing to any local fertile male dogs, but you protect her from their advances by making sure your home and back yard are secure. Avoid taking your female dog to places where there may be entire male dogs during their heat cycle.

Physical signs of the dog heat cycle commencing include a swollen vulva, discharge, bleeding and an increased urge to clean themselves. When you pet them your dogs tail will curve around over their back in an action called flagging. Your female dog might also surprise you by exhibiting more masculine traits during this time like humping, raising a leg to pee and may even become aggressive. However, most dogs in heat remain in great health and good spirits throughout their season. Female dogs are however vulnerable to health issues during the few weeks following each season, so you need to keep a close eye on your female at this time. And if your dog is coming into heat any more frequently than every four months it is worth speaking to your veterinarian, as this can be indicative of health problems.


How Long Does A Dog Stay In Heat?

Being in heat is also known as coming into season, and most female dogs will come into season twice a year throughout their lives unless they are spayed. These are averages however. Many factors which can influence the age at which your female dog starts her first heat, how long her heats last, and how often she comes into season

If your female puppy is nearing maturity and hasn’t been spayed, she is about to undergo some changes. We are going to dive into the world of female dogs to discover what your dog’s heat cycle involves. We’ll also explore how female dogs behave when they are in heat. You’ll find out what to expect from your dog’s first season, and how you can best care for your dog during this time.

Managing your Labrador in season is an important responsibility. With a little knowledge and planning, your dog’s time in heat shouldn’t have to cause you too many problems.

Do dogs have periods?

Female dogs don’t have a monthly periods or bleed in the same way that human females do. Bleeding is a natural aspect of their reproductive cycle but only takes place on average twice each year. The time during which this bleed occurs is called the heat or season.

Unlike most human females during a period, your female dog is highly fertile during their heat. This is the only time of the year during which dogs will mate and can conceive. So your Lab must be managed carefully during her heat in order to avoid pregnancy.

Your dog’s first heat

An unspayed Lab will likely have her first season any time from six months of age onwards. The average age is between nine and twelve months. Dog heat can start as late as eighteen to twenty four months old in larger breeds.

dog in heat

How often do dogs go into heat?

Your female Lab’s season will normally form a fairly regular pattern. Although the pattern may vary widely from dog to dog. The space in between seasons will usually be somewhere between every six months and annually. For example, one of our female dogs is every six months like clockwork. Another has only one season per year.

An eight to ten month cycle is longer than average but still considered to be normal. Occasionally a female dog will come into season every three or four months. Although the average is six months, variations in heat cycles is normal. However, it is a good idea to chat to your vet if your dog’s heat cycles are very different. This is especially true if they suddenly change to a new pattern. This is just a precaution in case there is an underlying health issue that needs looking at. Before we look at what to expect when your dog is in heat, you might find it helpful to understand how the dog heat cycle works.

The dog heat cycle – oestrus and proestrus

As she reaches maturity, your female dog produces hormones which sets a rhythm in motion. This hormonal rhythm controls the fertility of your dog and carries on throughout her life. This hormonal cycle is composed of four stages:

You can still have fun when with your dog in heat. Find out how to exercise her and keep her safe during her season
Being in season doesn’t mean no more fun – you’ll just need to exercise your dog in safe areas for a few weeks

The Anoestrus Stage of the Dog Heat Cycle.

This is the period of time when your female is not in season. It literally means ‘no heat’.
During this period your Labrador is not sexually attractive to male dogs and she cannot get pregnant.

The Proestrus Stage of the Dog Heat Cycle.

This is the first stage of her heat cycle. During this time her uterus (or womb) is being prepared for pregnancy. As her vulva swells and she starts to bleed, you become aware that she is in heat. During proestrus your female dog will be attractive to male dogs but not yet likely to willingly permit a male dog to mate with her.

The Oestrus Stage of the Dog Heat Cycle.

This is the second stage of the heat cycle. This is when your dog becomes fertile. At this point her bloody discharge may become paler and more watery. She will probably be willing to stand and allow a male dog to mate with her. Indeed she may be very flirtatious and encouraging to male dogs. Some females will actively seek to escape from their homes to find the boy dog of their dreams!

The Dioestrus Stage of the Dog Heat Cycle.

In a wild dog, this will almost always result in pregnancy and whelping. In domestic dogs, we usually prevent pregnancy. Indeed most Labradors never have puppies because Lab owners rarely breed their dogs.

During dioestrus the levels of progesterone that would normally support a pregnancy can cause problems. False pregnancy and infections of the uterus (pyometra) are very common during this period. At the end of dioestrus your dog’s hormones fall as she returns to anoestrus. These four stages will repeat each season.

Dog Heat Signs

There are usually some clear signs when your dog is in season, but it is not always obvious so if you think she might be approaching that time you need to keep an eye on her.

Physical appearance and swelling

The first thing you are likely to notice is that your female dog’s vulva (external genitalia) becomes very swollen and puffy. It may be literally three or four times its normal size.


Together with a bloody discharge, these symptoms tell you that your female dog has come into season. As your dog moves into her fertile phase, the bleeding may stop or become more watery. Although you might expect the main sign to be profuse bleeding, it isn’t always obvious. In fact, sometimes all you will see are very small markings on the floor or in the dog’s bed.

Increased cleaning and licking

Most Labs are very good at keeping themselves clean. This can provide another good sign that she is in season. If she is swollen as well as licking her genitals considerably more than usual, her heat has probably started.

Dog Heat Test

If you are not sure whether or not your Labrador is bleeding, gently wipe a piece of clean cotton wool or a white tissue over her vulva. You’ll probably see some pink staining if she is on heat, even if she is keeping herself pretty clean.

Dog Heat Behavior

You might notice a slight change in her temperament a few days before you see any physical signs that your dog is coming into season.

These could include increased sleepiness, or her showing more of an inclination to ‘be together’. Some female dogs will be very clingy to their owners around this time. Others will be more excitable than normal in response to the changes in estrogen. They may also show some odd behavior, such as cocking a leg to pee in the manner of a male dog.

Humping and flagging

Many female dogs will also hump other dogs, male or female, when they are on heat. Some female dogs, especially puppies, will hump other dogs in play. So, if there are no other symptoms, humping does not mean your dog is in season.

Flagging is when she turns her tail to one side when you run your hand down her back and over her rump. This behavior usually takes place during oestrus when she is ready to mate.

How long does your dog stay in heat?

If your female Lab is over four months old, here are some signs you can check for. One indicator is to check if she has a swollen vulva. Another is to check for pink staining when you wipe her vulva. This should be done with a clean white tissue or cotton wool. These are both signs that your dog is almost certainly on heat.

What to expect when your female dog is in heat for the very first time

If you experience any unusual or worrying behavior such as throwing up or loss of appetite, please consult your vet. It’s worth noting that being in season doesn’t increase your female lab’s need for calories.

If you are worried or not sure, do chat to your vet over the phone. Don’t take her into his surgery without talking to the vet first, in case there are male dogs in the waiting room. Your priority now is to make sure your dog in heat does not become pregnant. We’ll look at that in a moment. But first let’s find out how long dogs remain in heat.

How long will my dog stay in heat

The length of a season may vary. On average, your female dog’s heat will last approximately three to four weeks. The time that she will ovulate is about ten days to a fortnight in. At this point the color of her discharge may change from pink to colorless and her flagging will increase.

How long your female dog spends in each stage of her heat (proestrus and oestrus) varies widely from dog to dog. On average oestrus begins 7-10 days after the start of your dog’s season, but you simply cannot assume that she will be average.

Without getting your vet to carry out tests, it is very difficult to tell exactly when your dog is fertile. For that reason, you must assume she could get pregnant at any point after the first symptoms of heat appear. For the next three to four weeks, you should assume she could get pregnant.

Keeping track of your dog’s heat cycles

Make sure to record the date in your diary when your dog comes on heat. In addition, make a note that she may come on heat again in about six month’s time. That way you’ll be prepared and ready to look out for the signs in future. Many dogs do have a regular pattern to their cycles, which you will be able to spot with careful record keeping.

Can my dog have puppies in her first season

There is a risk of pregnancy during any time that your female dog comes into season. This includes the very first time.

If she is on heat, she will be susceptible to male advances, and may conceive if mated with.
But this does not mean that this is a good idea.

Most Labs are still puppies, very young and physically immature at the time they have their first season. It is not good for them to be mated at this stage.

There is also a greater risk of problems during whelping if they do conceive.

During her first season, your Labrador Retriever is likely too immature to cope with a litter of puppies. Nor is she likely to show good maternal instincts.

You will also find that some of the health tests you will need to have carried out to ensure the future safety of your dog’s puppies cannot be screened by this point.

If you are thinking of breeding from your Lab at some point, do check out this article for more help and guidance on making the right decisions.

Prevention Pregnancy During Dog Heat

A serious word of caution is required if you are intending to keep an entire male dog with an unspayed dog.

During her season they will need to be kept completely apart, ideally in a different house! Here’s why.

Separating your own dogs while your dog is on heat

You can try and separate your dogs at home. However, this can be a bit risky, depending upon your dog’s personality. It is also very easy to underestimate just how high a dog can jump if he really wants something special!

It is amazing just how quickly dogs can mate when you don’t want them to. All it takes is for one person to leave the door open for a couple of minutes.

Male dogs may become distressed

Your male dog will be able to tell that his female friend is on heat. He will be even more keen than normal to be in her company.

He may scratch and howl at the doors between them relentlessly, or pace up and down whining. This is both stressful for you to watch and listen to, and upsetting to both of your dogs.

Will brother and sister dogs mate?

YES! Please note, that dogs have no concept of ‘incest’. The fact that your dogs are brother and sister will not prevent them mating. If they do mate, any puppies will be greatly at risk from inherited diseases due to their similar genetic makeup.

But what about the morning after pill for dogs?

You might think that there will be an injection or pill that will put things right if you make a mistake and your dogs get together. Unfortunately, these hormonal injections have been found to be very risky for dogs and they are no longer used.

So if your dog gets mated, there is no easy way out the situation.

(paid link)
Exercise at home with lots of fetch – a Chuckit is great for keeping you going without tiring out your arm!

Alternatives to walks for dogs in season

A lot of people wrongly believe that it is harmful for their dog in heat not to be walked. This simply is not true provided the lack of exercise is temporary.

The Labrador Handbook by Pippa Mattinson(paid link)

As long as she is well stimulated both mentally and physically, your female dog will be fine going without a romp in the woods for a few weeks.

Plenty of dogs have to go on crate rest for weeks after surgery and survive without any ill effects.

And there are other ways to keep your dog occupied. Work on your training in a confined area, practicing heelwork and sit/stays, retrieving etc.

Clicker training is great for this, as it is a fun, rewarding way of improving training and occupying your dog’s brain too. If your dog doesn’t retrieve, you could even teach her to fetch while she is confined to home and yard.

(paid link)
Treat dispensing toys like this ball can exercise your dog’s brain.

Dog Menopause?

Dogs continue to cycle through the four hormonal phases throughout their entire life. So, if you don’t have your female dog spayed, she will continue to come into season every six months or so.

The Labrador Site Founder

Pippa Mattinson is the best selling author of The Happy Puppy Handbook, the Labrador Handbook, Choosing The Perfect Puppy, and Total Recall.

She is also the founder of the Gundog Trust and the Dogsnet Online Training Program 

Pippa's online training courses were launched in 2019 and you can find the latest course dates on the Dogsnet website


  1. Hi. I just thought I would let you know that female dogs are “spayed” not “neutered” as referenced in the first paragraph of your story.

    Hope this helps.

  2. Hi my Black female Lab will be 5 in April 2020 usually has 2 seasons a year, June and December….she had Junes one but had one in October instead of December one….she now has 4 of her boobs that are enlarged and hanging down near towards where her girly parts are…..the rest of her boobs/ nipples are very small but the bigger ones seem to be getting bigger, looks very weird and hasn’t happened before…..has anyone got any ideas what it is please, thank you…..

  3. my dog is Pomeranian 15 years old.she is on her period from past 2 months.the vet did ultrasound too but everything was normal. pls tell what to do

  4. My lab collie cross had a season in January at 6 months and 1 week. 3 months later, at the exam prior to spaying, the vet said she was lactating. That morning I had seen a small blood stain which the vet said was an infection and prescribed antibiotics. We delayed op for 2weeks.
    Over the weekend male dogs tried to mount her so second vet says she may be having a mini season. Is this possible when she is also lactating?
    Do some young dogs have irregular mini seasons?

  5. Is it possible for owners to sync up? My golden retriever is 16 months and just started her first season last night! But I have cramps now and it is not time… anyone else experience this?


  7. Dog nappies (diapers) are very expensive and even the extra large size is too small for a large dog. I found the absorbent pad material to be too far away from the tail hole. Therefore, the discharge from the vulva wasn’t caught.

    My solution:
    I stapled two Junior boy/girl nappies together and cut a hole for the tail. This resulted in a more generous nappy that did the job better and was way cheaper.

    • I bought some from amazon and there great my girl is not the biggest of labs but she wears them no problem they came in a pack of 3 so I wash two at a time so always got one on . No mess found all caught and she can get under them to clean herself also which I think is important

  8. Hi I have a August born indie. She is 9 months old. She started bleeding 10days ago & still bleeding. her bleeding is still the same dark red. It’s not fading into light pink nor thin in texture. Is it normal or I should contact the vet immediately. Please reply as I’m worried as hell

  9. My female lab is 20 months old and just finished her 2nd heat cycle about 3 weeks ago. I notice that she is much more aggressive and rough during play and that she just does not seem to want to play at all with other dogs. Is this normal and will this decrease as her hormones start to level off again. She used to love playing with other dogs and not it seems she would just rather be off on her own. Is there anything I can do to help her through this time? She is a sweet and well behaved girl and usually loves to play and interact with other dogs.

    • My 9 month old Pitbull as well as my mother-in-law’s 1 yr. old Shepherd are both very stinky right now, about 2 weeks into their heats, I do think it’s normal, but I’m no pro 😉

  10. Thanks for the clear, comprehensive info. One question: our Molly started in to heat two days after turning one year old. 10 days later, she has shown little interest in her kibble, but likes bully sticks and rawhide and apple slices and just about everything else. So, she’s not eating nearly as much as before going into heat. One site mentions that a dog in heat may lose appetite. Thoughts?

  11. Doggy menopause. My old girl Hannah had 13 happy years. She was never spade and had one litter. That’s a lot of heats! If I had known about pyro I would have had her spade in middle age. However her heats became shorter and then farther apart and then stopped at ten years old.

  12. Hi, my lab was 8 months old when she began her first season….that was almost 2 months ago! Her vulva is still very swollen…is this normal or should I get her checked out

  13. my female is now 2 years old. I do not think she has come into season at all. At 1 year she was acting like it, but not fully.
    Is there anything I can do to bring her in? I would truly like to have a litter from this exceptional animal.

  14. My lab is just one year and started her bleeds last week. she swallowed a sock and is now thowing up all her food now, Im not sure wheter she is bleeding internally, there is a terrible smell fom her breath and she coughed up bloody substance now its browny took her to vet today and he gave her injection for inflammation
    Worried owner just got her at 6 months following the parting of our 8 year old lab who died starting with heavy bleeds lasted 3 days,

  15. Our Indi has just gone into her first season and our neutered 6 year old male is very interested. Whist she can go in her crate I really don’t want to keep her locked up for a potential 4 weeks !
    Will he lose interest as I don’t want her bullied ?
    Any advice welcome please.

  16. My 9 month old is 12 days into her first season. She seems to be in the second stage of heat as the bleeding has almost entirely stopped and is much more pale now. My question is more about her mood. She is keeping to herself a lot which I gather is normal but has now gone off her food and is not drinking much. I am giving her cooked chicken in lots of chicken flavour water but she doesn’t particularly want even that. She is definitely fed up with the lack of walks and doesn’t want to chase a ball around the garden. She will still play training games though. I have spoken to the vet and will take her if she can’t keep her fluids up but wanted to check if there are any other thoughts about this behaviour and whether it is normal? Many thanks.

    • Hi Elaine, it is possible, but if she doesn’t eat for more than 24 hours or seems uncomfortable, or unwell, you really need to take her to the vet.

    • I Elaine,

      Would only suggest you to please get your girl checked up for Pyometra as going off of water or loss of appetite is the early sign for the same.

  17. Thanks for this article. It was extremely helpful. Our girl celebrated her first birthday by going into season. We have all survived!

  18. My lab puppy started her first season on Feburary 1st, a week short of her first birthday. Everything seemed normal…bleeding for 11 days, then pinkish for a few days. Swelling went down, but we waited a full 4 weeks. We took her on outings on starting on the 28th. She started bleeding again on March 5th and was very swollen. She is still swollen and bleeding. I am assuming this is a case of back to back seasons. Will she still be fertile for 21 days?

  19. Hi my b***h is 10 months old she started bleeding 1 week ago and since then her behaviour has changed immensely. She growls and snaps at me my husband and children if we go near her. She was perfectly fine before she came into season but she actually scares me i have to keep her caged in fear she may bite. Is this normal behaviour or should i be concerned. Thank you

    • Hi Lindzi, Labrador behaviour can change when they come into season but this doesn’t sound normal to me. The best thing to do is take her to your vet, who can make sure it isn’t a medical issue and refer you to a behaviourist if necessary. Wishing you the best of luck. Lucy

    • Maybe you shouldn’t call her your b***h !!! I know a female pup is a B…..! It just sounds SO NOT RIGHT! I know a sweet name for her? What about Kimmy ☺️ That’s Super Cute ? Have a Blessed Day .

      • Hi Gail, It’s actually a technical term that is in common usage in the UK for a female dog. However, I appreciate that elsewhere it can be seen as very offensive, so I have edited your comment and theirs to reflect this. Best wishes, Lucy

    • My b***h also came in to heat about 2 weeks ago and is also still bleeding, I have been told that this is perfectly normal so long as the bleeding is not heavy, if the bleeding is heavy then you should get her checked.

  20. My b***h is about to come into heat. My vet mentioned an injection that can reduce it to 5 days once she gets the first signs. Is this safe and can it be repeated?

  21. My borador puppy is 5 months old and I have noticed spots of blood on her puppy training pad the last 2 days. Is she in heat or is it just bleeding gums?

      • Thanks, it was just bleeding gums. She is now 11 months and has been in heat for at least the last 3 days. Noticed blood Friday morning.

  22. Hi Pippa, thank you for all the useful info you provide. I find your articles enlightening, especially those on spaying/neutering.

    My question is that i noticed my lab go into heat on September 17th. It is her first heat and she will be 1 year old this week. First there was bleeding, (slightly heavier than I’m used to), then she was receptive but that phase was over quickly. She has spotted all through her period. It seemed like it was over nearly a week ago, but today (October 18th) is day 32 and she is bleeding again. It just appears like blood, nothing cloudy or slimy. She also is not energetic as usual, and her appetite wasn’t great today. I’m a bit concerned. Do you think this requires a visit to the vet? I’m torn because a couple of days ago we returned from a prolonged visit at my family’s home where there are people and other dogs she loves. I can’t tell if it is her health or if she’s just missing them.

  23. My Fern is just 10 months of age, and I’ve just noticed the first blood spots, and her vulva is definitely distended. My question is, will this have any effect on Polly, my spayed 3 year-old.

  24. My Oly got on her first heat 30 August at 9 months. My concern is that her bleeding hasn’t stopped as yet. It’s been over 10 days now. She’s behaving just fine.. Nothing wrong otherwise. Just wondering when the bleeding will stop since it hasn’t even started fading away. Bloody dots are still dark/bright red. Please let me know what to expect next. Thanks in advance!

  25. Hi Nala is 1 year and 10 months and in season, with visible signs since the 2nd. I did notice though that at least 1 week/10 days before she was extremely clean with her private parts and my entire dog was pretty interested but there were no signs at all. 2 months before she was doing the same and so my male dog, at the time I took her to the vet and he said there was absolutely no sign. So this time round, no signs at all, I assumed it was the same as before. Eventually on the 2nd while she was fast asleep legs up in the air I curiosily went to check her as Rufio was not that interested anymore even if other dogs did seem a bit on walks, and I saw some drops of blood! I am now very careful with them alone and Rufio has been chemically castrated immediately and seems to be nearly disinterested in her. She is still bleeding even if sometime like you said is reddish/brownish or pinkish. She has been doing wee much more often before I found out and even now as you said. How am I supposed to know how long it will last and will she still be in season when there are no more signs?! It’s now 5/6 days with signs but at least a week before this she was weeing more and cleaning herself like mad! Do you think she could be already pregnant as before this bleeding I didn’t pay much attention and left them alone at home at times?!Or as she is bleeding she is not pregnant?!Thanks Pippa, looking forward to your answer.
    For whoever needs them I have found some very intelligent(maybe not pretty) pants and that keeps the house clean as I can change the little pads whenever I want, I take them out when we walk and in the garden.The make is Mikki and off course labs will need the large or extra large pants and pads. You can buy them in Petsathome or other good shops.

  26. I have a black lab that went into season for the first time a week ago and she is 3 years old, should I be concerned?

  27. I have a yellow lab that is four years old. My question is while she’s in heat she looks to me like she’s miserable. Do female dogs feel any discomforts while they are in heat?
    Thank you

  28. My chocolate labrador is 1 and a month old she has always been a very clean puppy from 6mobths on ward. But I have never noticed any bleeding or swelling of any body parts or increase attention from the boys. She is always a cuddly ball of fur and likes our attention. So I assume she hasn’t seasoned yet should I be concerned?

    • No Mariette, it is quite normal for the first season to take place towards the end of the first year or the beginning of the second. It will probably be any time soon. 🙂

      • our yellow lab who turns 1 on March 16th just went into heat today… We were getting concerned as well. We knew that a couple of other babies for her litter had already gone into heat and she hadn’t yet… I would say your baby will go into heat any day now.

  29. Hi, my female lab is 5 months old and just come into season. Is this normal? She seems a bit young to be having a season already?

    • My labrodor molly came into season to at 5mths, but had no bleeding. She is now 9 1/2 mths old & in a fully season. So dont worry yr little girl is fine

    • Our girl is only 4.5 months and she is now in the middle of her first season. I am also a little bit worried about that, not sure if it’s normal.
      We were planning to have her spayed next month before her first heat.

  30. I have noticed my 10 month old lab cleaning herself more lately, and this morning cleaning her after a run in have noticed some blood. It looks a wonderful 3 weeks trying to distract her from not going for our usual long walks.