My Dog Is in Heat: Signs, Management Tips, and What I Needed to Learn

We adopted Pepper, our new lovely Rottweiler mix, two weeks ago. I knew she was two years old and intact. Without any further details, I wondered when she might go into her heat cycle. As it turns out—right now.

Most dog parents never experience their girl going into heat because of standard early spay and neuter. We’ve never had an intact adult female dog. In my ignorance, I assumed that the way she looked was simply how an unspayed female looks. But yesterday, we noticed some drops of blood in the snow.

In the past, the first thing I would have checked was her feet. More than once, one of our dogs had cut a paw on something sharp. But this time there was too little blood for that.

And then it dawned on me. My dog is in heat.

Is that why she’s been so hungry? Until today, she was the same as the day we brought her home—a sweet little pocket-rocket velociraptor hybrid. Today, she’s been a bit quieter—hard not to notice.

What Being in Heat Means?

Being in heat is a normal part of the reproductive cycle in intact female dogs, when the body is prepared for pregnancy.

Most female dogs experience their first heat sometime between six months and two years of age, depending on breed and size. Larger breeds often cycle later. After that, heat typically occurs roughly every six to eight months.

A heat cycle usually lasts two to four weeks and unfolds in stages. Understanding the general progression helps make sense of what you’re seeing.

Length of heat cycle varies by breed. Small breeds like Chihuahuas may cycle every 4–6 months and start earlier, while giants like Great Danes often later.

Breed size (examples)	First heat age (average)	Cycle frequency (average)
Small (Chihuahua, Yorkshire Terrier, Pomeranian)	4–7 months	Every 4–6 months (2–3× per year)
Medium (Beagle, Cocker Spaniel, Bulldog)	7–12 months	Every 6 months (twice per year)
Large (Labrador Retriever, Rottweiler, German Shepherd)	12–18 months	Every 6–8 months (1–2× per year)
Giant (Great Dane, Mastiff, Saint Bernard)	18–24 months	Every 8–12 months (sometimes once yearly)
Exceptions (Basenji, Tibetan Mastiff, Dingo)	6–12 months	Once per year

Dog Heat Cycle Definitions

Did you know that the word estrus comes from the Greek oistros, meaning “frenzy” or “mad passion?” Estrus is driven by intense hormonal shifts that can affect behavior, appetite, focus, and sensitivity, sometimes in ways that feel sudden or exaggerated.

• Proestrus literally means “before estrus” (pro- meaning before), when the body is preparing but ovulation hasn’t occurred yet.
• Diestrus comes from di- meaning “two” or “between,” reflecting the post-estrus phase when hormone levels shift again, whether or not pregnancy occurs.
• Anestrus combines an- meaning “without” with estrus—this is the long resting phase between cycles.

Further reading: Dogs In Heat: Timeline, Duration, and Symptoms
The estrous cycle in the dog: A review
Abnormalities of the Canine Estrous Cycle: A Review

Peeling the Onion

Under normal circumstances, you know your dog and can tell what is normal and what is different. But we just adopted this girl.

When Pepper came to us two weeks ago, she was sweet, affectionate, and skittish. From the beginning, she’s also been acting as if she were starving—despite being described to us as a dog who liked to savor her food.

She also had to pee every hour and poop every two hours. Her stools were solid but yellow in color—her elimination habits have since mostly normalized. She’s very comfortable with us.

My Dog Is in Heat: Appetite

An impending heat cycle can affect your girl’s appetite—or not at all.

These changes can happen before any outward signs of heat. Your girl may seem unusually hungry, less interested in food, or oddly focused on eating behavior (hovering around food, acting preoccupied with meals) weeks ahead of the cycle.

These changes can be due to stress, adjustment or behavioral quirks, especially in newly adopted dogs, or dogs experiencing other routine changes at the same time. That leaves the cause of Pepper’s ravenous hunger to anybody’s guess.

Whether appetite goes up, down, or stays the same depends on how an individual dog responds to the cycle-related hormonal changes—and all three responses can be normal.

Further reading: Estrus Cycle, Pyometra, and Insulin-Resistant Diabetes in the Bitch: What is Known and Why it is Relevant?

My Dog Is in Heat: Thirst and Urination

Hormonal shifts during heat affect more than reproduction. Estrogen and progesterone influence fluid balance, kidney function, and behavior, which can subtly change how much your girl drinks and, in turn, how often she urinates. However, it’s important not to miss the forest for the trees.

Heat-related thirst and urination changes are usually mild, short-lived, and improve as the active heat phase passes.

Energy Level/Activity Changes During Heat in Dogs

Changes in energy and activity are common during a heat cycle—and they can go in either direction. Beyond reproduction, hormonal shifts affect the nervous system, metabolism, and stress response. As a result, some dogs seem wired, while others seem wiped out.

Some dogs bounce between restlessness and fatigue during the same cycle. A dog may seem unusually energetic one day and noticeably tired the next.

Pepper has been an unwavering pocket rocket since the day she came to us. We are worn out by trying to provide her sufficient physical and mental stimulation, and she is not. Whether, and in which direction, this will change, remains to be seen.

Vaginal Discharge During Heat: What’s Normal and What’s Concerning

Vaginal discharge is one of the most apparent signs of the heat cycle and changes by stage. Variation is normal. Some dogs bleed a lot. Others barely at all. With Pepper, all we’re finding is the odd drop here and there. But she also works hard on cleaning herself.

Will My Female Dog in Heat Roam?

Some females in heat will actively seek males. Many do not. It is individual, phase-dependent, and temperament-dependent—but it is a real risk during estrus.

Temperament matters

Confident, independent dogs mean higher roaming risk. Meanwhile, anxious or handler-focused girls present lower risk. A girl in estrus doesn’t need to see or hear a male. She will respond to residual scent markers, not proximity alone.

Male dogs leave urine markings that can remain detectable for days to weeks, depending on temperature, moisture, wind, surface (soil, grass, snow, urban substrates). During estrus, a female’s sensitivity to these scents increases dramatically. What was previously background smell can suddenly become salient and directional. She’s following information, not impulse.

How far will she go?

Most females do not travel extreme distances but some might go farther than their normal range. Your girl is more likely to try to slip a door, dig under a fence, or bolt during an off-leash moment.

In areas with coyotes, be especially cautious during estrus, as reproductive pheromones are not species-specific.

Pseudopregnancy (False Pregnancy) in Dogs

After estrus, a dog’s body does not immediately “know” whether pregnancy occurred. Progesterone remains elevated during, followed by a drop that can trigger hormonal changes similar to those seen during pregnancy.

In some females, this leads to pseudopregnancy (false pregnancy).

This is a normal physiological response—not a disease—but the symptoms can be confusing or concerning, especially if you’re seeing them for the first time.

How Long Does Pseudopregnancy Last?

Symptoms usually appear 2–8 weeks after estrus and resolve on their own over 2–3 weeks, though mild signs can linger longer.

T Minus Spay Day: Timing Matters

We planned on getting Pepper spayed as soon as she got settled in. She’s two years old, fully developed—clearly. Biology, however, temporarily threw a wrench into the works.

Pepper’s heat now defines the schedule and pushes it to her upcoming anestrus.

During proestrus and estrus, the reproductive tract becomes highly vascular. The uterus and surrounding tissues are engorged with blood, which increases the risk of bleeding during surgery and makes the procedure technically more challenging. That makes spaying Pepper while she’s in heat out of question, unless there is a medical emergency.

Since we’re waiting anyway, it makes sense to wait for the optimal window.

Although spaying during late diestrus is considered reasonable by many veterinarians, I prefer to wait until Pepper’s body has fully returned to baseline—when hormone levels have stabilized and surgical conditions are calmest.

Related articles:
Canine Spay and Neuter: To Neuter Or Not To Neuter… That Is The Question
CCL Tears And Early Spay And Neuter: Is There a Connection?

Vaccinating during Heat Cycle: Is It Safe?

We didn’t get much of Pepper’s medical history. It looks like she probably had her puppy vaccines and maybe her 6-month boosters. That’s about it.

She should have received another round about a year later, so we need to catch her up. The plan was to start at her first vet visit with us. But now she’s in heat. Does that change anything? Not really.

Vaccination safety and the risk of adverse reactions are not meaningfully different during a heat cycle. Vaccine reactions depend more on things like:

• immune sensitivity
• prior exposure
• genetics
• size/breed tendencies
• vaccine type
• individual “that dog always reacts to everything” personality

While vaccinating during heat is typically safe there is an important consideration of the type of vaccine. Inactivated (killed) vaccines are generally considered safer than live ones, as hormonal fluctuations might cause mild immune suppression.

The other drawback is practical, not medical. During heat, it can be harder to tell what’s a normal hormonal shift and what might be a vaccine reaction.

In Pepper’s case, staying protected matters more than waiting for ideal timing. However, our veterinarian agreed with my sentiment and while the original plan was to start with Rabies shot followed by DAP, we switched them around and gave Pepper DAP first.

My Dog Is in Heat: Practical Management Tips

Coping with a girl in heat is mostly a management issue. A few temporary adjustments make life easier for everyone.

Pepper’s Heat Cycle

We made it through Pepper’s proestrus and estrus uneventfully. She was a good girl and never showed any interest in chasing boy dogs, which made it easier on all of us.

Her proestrus lasted 12 days and estrus 10 days.

Incidentally, we learned that this was her fourth cycle. With each cycle, it becomes more important to stay vigilant for potential pyometra.

Note on Silent Heat

Not all heat cycles look dramatic.

Some females go through what’s called a silent heat, where the outward signs are minimal. There may be little to no swelling, very light discharge, or behavior changes so subtle they’re easy to miss. Yet hormonally, the cycle is still happening.

Silent heats can lead owners to believe their dog “skipped” a cycle. In reality, ovulation may still occur, and the same post-heat risks—including pyometra—still apply.

If your dog’s cycles seem irregular, unusually mild, or difficult to track, discuss it with your veterinarian. Keeping a written record of cycle timing can help you spot patterns over time.

Note on Behavioral Changes (or the Lack of Them)

Not every female shows obvious behavioral shifts during heat.

Some become restless, vocal, clingy, or actively seek out male dogs. Others go through the cycle with very little change in temperament. The physical signs—swelling and discharge—may be present, but the personality remains steady.

A calm heat does not mean the cycle is incomplete. Ovulation still occurs, and the same post-heat risks apply.

Tracking timing and signs—even when they’re mild—helps you understand what is normal for your individual dog.

Did you ever have a dog in heat? What is your experience?

Related articles:
Dog Sick after Heat Cycle: Miku’s Story. What Would You Do if It Was Your Dog?

Further reading:
Dog Heat Cycle: Length, Frequency, and Stages