Heat Cycle in Female Dogs: What Happens and How to Help Her Through It
- 1 day ago
- 4 min read
Is your female dog suddenly licking herself more, urinating more often, and you've spotted a few drops of blood on the floor? If this hasn't happened yet, it eventually will — heat is a natural part of every unspayed female dog's life cycle.
Yet it's still surrounded by confusion: how long it lasts, what's normal, and when it's time to call the vet. Let's walk through it step by step.
What heat is and what happens in her body
Heat (medically known as estrus) is a hormonally driven period during which a female dog is able to become pregnant. It's governed mainly by the hormones estrogen and progesterone, whose levels shift over several weeks and gradually prepare her body for possible fertilization. Unlike humans, female dogs don't have a monthly cycle — they typically go into heat only once or twice a year.
The four stages of the heat cycle
Proestrus (about 7–10 days): bloody discharge appears, the vulva swells noticeably, and males are drawn to her, but she still refuses them.
Estrus (about 5–14 days): the discharge lightens, she is fertile and receptive to mating — this is the stage when unwanted pregnancy is a real risk.
Diestrus (around 2 months): her body returns to a resting state; this is also the stage when false pregnancy most often shows up.
Anestrus (several months of rest): her body rests until the next cycle begins.
How old is a female dog at her first heat, and how often does it happen
The first heat usually arrives between 6 and 12 months of age, though large and giant breeds may start later, around 18–24 months. After that, the cycle typically repeats every 6–8 months, though for some dogs and breeds (such as Basset Hounds or Bloodhounds) the interval can be longer, around 12 months. It's completely normal for two dogs of the same age to have very different heat schedules.
How to tell your dog is in heat
A swollen, reddened vulva
Bloody to pinkish discharge
Frequent licking of the rear end
More frequent urination and territorial marking
Increased interest from unneutered male dogs nearby
Mild mood changes or a temporary drop in appetite
How to care for your dog during her heat
Use hygiene diapers or pads if the bleeding bothers you on furniture or carpets.
Walk her on a leash and avoid areas where unneutered males roam — even a single unsupervised mating can lead to an unwanted pregnancy.
Limit visits to dog parks and group walks for the duration of her heat (usually 2–3 weeks).
Keep her clean, but don't punish her for more frequent marking — it's natural hormonal behavior.
Watch her mood and appetite — small fluctuations are normal, bigger changes are worth noting.
A female dog can be fertile even outside the days of heaviest bleeding, so staying cautious throughout the whole heat — not just at the start — really pays off.
When to be concerned and call the vet
Most heat cycles pass without complications, but a few warning signs shouldn't be ignored:
Discharge that's green, pus-like, or has a strong odor
Fever, lethargy, or a marked loss of appetite
Bleeding lasting more than 4 weeks, or discharge returning after the heat has ended
Signs of false pregnancy appearing after heat — enlarged mammary glands, nesting behavior, restlessness
Suspected unwanted mating — in that case it's best to discuss next steps with a vet as soon as possible, including what giving birth would involve.
In older, unspayed females, the risk of a uterine infection (pyometra) also increases with each additional heat cycle, and it can appear even some time after the heat has ended. This is a condition that needs prompt veterinary attention, so don't wait if your dog seems to be declining after a heat cycle.
Spaying as a solution
If you're not planning to breed and heat cycles are more of a burden than anything else for you and your dog, spaying is the answer. It eliminates heat cycles entirely and significantly lowers the risk of mammary tumors and the pyometra mentioned above.
You can read exactly what spaying involves, how it's performed, and how long recovery takes in Kastrace feny: co byste měli vědět (our Czech-language guide to spaying), including how to manage bolest po kastraci feny (pain after spaying).
Frequently asked questions about heat in female dogs
Can a dog get pregnant during her very first heat? Yes, technically she can, although breeders usually wait until a young dog is physically mature before allowing mating.
How many times a year does a dog go into heat? Most dogs go into heat once or twice a year, though the exact interval varies by individual.
How long does heat last? Around 3 weeks in total, although the individual stages can vary from dog to dog.
Can a dog be spayed while in heat? Vets usually recommend waiting for a resting phase, since the uterus is more engorged with blood during heat, which makes surgery riskier.
If you're not sure whether your dog is doing well, or you're considering spaying and want advice, we can come directly to your home, or discuss it remotely. Book a home veterinary visit, clinic examination, or an online telemedicine consultation. You'll find more helpful articles on our blog.
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Note: All information provided on this website is for educational purposes only. None of the information here is intended to replace a medical diagnosis and should not be considered medical advice or a recommended treatment.
* Image source: Google Gemini
