How Long Do Dogs Stay in Heat?
A dog's heat usually lasts about two to three weeks (14 to 21 days), and most dogs come into heat roughly every six months. Small breeds may cycle about three times a year, while giant breeds may only cycle once. The fertile window when she can get pregnant is the middle stage (estrus), but she should be kept away from intact males for the whole heat to be safe.
Most female dogs stay in heat for about two to three weeks - roughly 14 to 21 days - though the exact length varies with breed, age and the individual dog. During this window she is fertile for part of the time and can become pregnant, so an unspayed female needs careful supervision throughout.
How often do dogs come into heat?
On average, a female dog cycles about every six months, but this depends heavily on size:
- Small breeds may cycle more often - sometimes about three times a year.
- Giant breeds may only cycle once a year.
Cycles are often irregular for the first year or two after a dog’s first heat, then usually settle into a predictable pattern.
The four stages of the heat cycle
| Stage | Typical length | What happens |
|---|---|---|
| Proestrus | ~9 days | Swollen vulva and bloody discharge begin. She attracts males but will not allow mating yet. |
| Estrus | ~9 days | The fertile stage. Discharge lightens to pink/watery, and she will accept mating. This is when pregnancy can happen. |
| Diestrus | ~60 days | Fertility ends; swelling and discharge stop. If pregnant, this is when pregnancy progresses. |
| Anestrus | ~4–6 months | The resting phase between cycles, with low hormone levels. |
When people say a dog is “in heat,” they usually mean the proestrus and estrus stages together - the two to three weeks of swelling and discharge.
Signs your dog is in heat
- A swollen vulva
- Bloody or pinkish vaginal discharge
- More frequent urination and marking
- Increased licking of the genital area
- Restlessness, clinginess, or changes in mood
- Extra attention from male dogs
Caring for a dog in heat
- Supervise closely. Keep her securely away from intact males for the entire heat - not just the fertile days - because timing is hard to judge exactly.
- Leash walks only. Don’t let her off-lead in public; her scent draws males from a distance.
- Manage the mess. Doggy nappies or a washable bed cover help with discharge.
- Extra comfort. Some dogs are clingy or unsettled - a quiet space and normal routine help.
Should you spay?
If you don’t plan to breed, spaying removes heat cycles entirely and greatly reduces the risk of certain cancers and a serious womb infection called pyometra. Talk to your vet about the right timing for your individual dog. See our related answer on whether dogs get periods for how the heat cycle compares to a human period.
References
- How Long Are Dogs in Heat? - American Kennel Club
- Estrous Cycles in Dogs - VCA Animal Hospitals
- Dog in Heat: Timeline, Duration, Symptoms, and Care - PetMD
This article is general information, not veterinary advice. Ask your vet about heat cycles and spaying for your individual dog.
