Dog Heat Cycle: How Long It Lasts and How to Care for Her
A female dog's heat cycle is a natural reproductive cycle that occurs around twice a year, roughly every 5-11 months. Small breeds tend to cycle more often, large and giant breeds less often. The full cycle has four stages (proestrus, estrus, diestrus, anestrus), and the visible heat with bleeding usually lasts about 2-3 weeks. During estrus she is fertile and can get pregnant, so she needs constant supervision.
A heat cycle is not an illness and not a reason to panic - it is a normal part of life for an unspayed female dog. But it does ask something of you: a bit more hygiene at home, a lead on every walk, and real vigilance if you are not planning puppies. Here is the whole picture in order: how often, how long, what is happening inside her, and when spaying enters the conversation.
How often does a dog come into heat?
Most female dogs come into heat roughly twice a year, on average every 5-11 months. That is a simplification, though, because the rhythm depends on size and breed:
- small breeds - often cycle more frequently, up to three times a year,
- large and giant breeds - usually cycle less often, sometimes only once a year,
- a few breeds (such as the Basenji) naturally have a single heat per year.
The first heat usually arrives between 6 and 24 months of age - small dogs mature earlier, big dogs later. In a young dog the early cycles can be irregular, and it takes a few rounds before they settle. The best thing you can do is record the dates - your own log will tell you more than any general chart.
The stages of the cycle
Heat is the everyday name for the part you can see, but the full reproductive cycle has four stages. Here are the rough timeframes:
| Stage | Duration | What happens |
|---|---|---|
| Proestrus | about 7-10 days | Swollen vulva, blood-tinged discharge. She attracts males but will not accept mating |
| Estrus (heat) | about 5-14 days | The fertile window. Discharge lightens, she accepts mating - pregnancy is possible |
| Diestrus | about 60-90 days | The post-ovulation phase. She is no longer attractive to males, hormones settle |
| Anestrus | about 4 months and up | The resting phase. Hormones are low, the body recovers before the next cycle |
In practice, the key difference is between the first two stages. Bleeding starts in proestrus, but it is only during estrus that she is fertile. Importantly, ovulation does not always line up with the moment the bleeding eases off - so you cannot eyeball the day when the risk of pregnancy disappears.
How long does heat last?
The visible heat - the stretch with bleeding and a swollen vulva - most often lasts 2-3 weeks. The fertile days usually fall in the second week, though this is highly individual. The full cycle, including that long resting phase, stretches across several months.
If the bleeding is very heavy, drags on far longer than usual, or comes with lethargy, fever, increased thirst or unusual foul-smelling discharge - do not wait, call your vet. Those signs can point to a health problem such as pyometra (a uterine infection), which is a life-threatening emergency.
Care and hygiene during heat
The good news: a healthy dog handles much of her heat on her own. Your job is support and keeping the situation under control.
- Hygiene - most dogs keep themselves clean by licking. If bleeding is marking your home, dog season pants with a liner can help. Do not force extra baths on her.
- Walks on a lead - this is not the time for off-leash freedom. Her scent travels far and draws in intact males. Pick quieter routes and quieter hours.
- Away from other dogs - skip dog parks and group meetups. A dog in heat can be restless, or the opposite, more withdrawn, and the presence of males only raises the temperature.
- Comfort and calm - some dogs get more irritable or sleep more during this time. Give her a quiet place to rest.
- Fresh water and her normal diet - appetite may swing a little, but keep an eye on any big changes in eating or drinking.
Heat is also a good moment to think about her wider health care - an up-to-date vaccination schedule and regular check-ups are the foundation you build everything else on.
The risk of pregnancy - do not underestimate it
This is the single most important point for anyone not planning puppies. During estrus she is fertile and can get pregnant, and the determination of an intact male dog can be startling. A brief moment unsupervised in an unsecured space is all it takes.
In practice that means: a lead for the entire heat, a secured garden (males will work hard to get over and under obstacles), and full control on walks. An unintended mating is not just a headache for you - it is a genuine health risk for a young or frail dog.
When is spaying considered?
Spaying removes the ovaries (often the uterus too), so hormones stop being produced and the heat cycle stops completely. It also eliminates the risk of pyometra and lowers the risk of certain mammary tumours.
When should it be done? This is a question with no single right answer for every dog. The best timing depends on breed, size, sex and individual health, and research into the effects of earlier versus later spaying is still evolving. Make the decision together with your vet, not based on a forum thread or a generic guide. The same goes for behaviour - spaying is not a magic fix for behavioural problems. We cover the procedure itself, with its pros and cons, in our guide to neutering and spaying dogs.
If you plan for your dog to spend time around other dogs, healthy socialization matters too - outside the heat period, on calm and controlled terms.
Heat passes, and the energy comes back. When she is ready for the world again, open DOGOUT to find calm routes and spots nearby, match a walk to her temperament, and head out for something more than a loop around the block.
Frequently asked questions
- How often does a dog come into heat?
- Most female dogs go into heat around twice a year, on average every 5-11 months. Small breeds often cycle more frequently (up to three times a year), while large and giant breeds usually cycle less often, sometimes only once a year. It varies by individual, so it helps to track the dates.
- How long does a dog stay in heat?
- The visible heat, with bleeding and a swollen vulva, typically lasts about 2-3 weeks. The full reproductive cycle, including the resting phase, spans several months. The fertile days usually fall in the second week.
- When does a dog have her first heat?
- Usually between 6 and 24 months of age. Small breeds mature earlier, large and giant breeds later. If the first heat is well overdue past that window, check with your vet.
- Can a dog get pregnant during her heat?
- Yes. During the estrus stage she is fertile and will accept mating. She needs constant supervision in this period and should stay on a lead anywhere intact male dogs might appear.
- Can you still walk a dog while she is in heat?
- Yes, exercise is good for her, but keep her on a lead and away from off-leash dogs. Choose quieter routes and times. Remember that her scent attracts intact males from a long distance.
- Does spaying stop the heat cycle?
- Yes. Spaying removes the ovaries (often the uterus too), so hormones are no longer produced and the heat cycle stops completely. The right timing depends on breed, size and the individual dog, so decide it with your vet.
