How Often Is Dog Heat Cycle?

It’s not a personality shift. It’s probably her heat cycle.

Female dogs don’t ovulate every month like humans. But they do follow a cycle. And it’s driven by hormones, not mood swings. These shifts affect behavior, energy levels, and even how your dog interacts with her leash or other pets.

Understanding the heat cycle isn’t just for breeders. It helps with basic care, canine reproduction decisions, and preventing surprise litters, especially if your puppy is getting close to maturity. It also helps you spot when something feels off and when it’s time to call the vet.

What is a Heat Cycle?

A heat cycle is your dog’s natural way of getting ready for fertilisation. It’s part of canine reproduction, and it affects everything from hormone levels to behavior. You might also hear it called the “estrus cycle.” 

What you should know is that this cycle happens in four parts.

• Proestrus is the start. Estrogen levels rise. The vulva swells. Appetite might drop. Male dogs start showing interest, but she’s not ready.
• Estrus is when ovulation kicks in. This is the fertile window. You’ll notice more behavior changes here. She may act restless or clingy. Some dogs seem flirty or even more responsive during dog training.
• Diestrus is the wind-down phase. Hormones shift again. If she’s not pregnant, her body returns to baseline.
• Anestrus is the break between cycles. It’s quiet. Her uterus rests. No bleeding, no mating behavior, and no hormone spikes.

Each phase affects her mood, energy, and health. And while this all runs on a schedule, it’s not the same for every dog. Age, dog breed, and size play a role, too.

How Often Do Dogs Go Into Heat and When to Expect the First One

Not every dog follows the same calendar, but there’s a rhythm to it. Most dogs go into heat about twice a year. Some more. Some less. And that rhythm starts earlier than you might think.

Most dogs: every 6 to 8 months

The average female dog will go into heat roughly every 6 to 8 months. It’s part of her natural cycle once she reaches puberty. That timing isn’t exact. But it’s a solid baseline.

Smaller breeds tend to cycle more often. You might see signs like vaginal bleeding, mood changes, or instinct-driven behavior every 3 to 4 months. Larger breeds, like Tibetan Mastiff, take their time. Some only cycle once a year.

This doesn’t mean anything’s wrong. It’s just biology doing its thing. Hormones shift. The mammary glands are prepared. The body gets fertile, even if you have no plans for breeding or future partners.

If the cycle feels unpredictable, track it. Hygiene practices, behavior patterns, and even diet can help you stay ahead of it.

First heat usually hits around 6 months old, but not always

Most dogs hit their first heat between 6 and 9 months. That’s when puberty kicks in and everything starts moving. You might notice changes in dog behavior, appetite, and even pain sensitivity.

But if your dog is a giant breed, don’t be surprised if it takes longer. Some don’t start until 12 to 18 months. And that’s still considered normal.

If she’s over 18 months with no heat signs, it’s worth a quick check-in with your vet. Veterinary medicine can rule out any underlying issues.

Nutrition, weight, and even kennel stress can delay the first cycle. So give it time. But keep an eye out.

Signs that Show Your Dog’s in Heat

When a dog hits sexual maturity, her body gives off a few clear signals. They’re easy to spot once you know what to look for. Most signs last around 2 to 3 weeks. Some shorter, some longer, depending on the dog breed and her individual cycle.

Here’s what you might notice:

• Swollen vulva: One of the first physical changes. It’s usually painless but looks more noticeable than usual.
• Light bleeding or discharge: This can range from faint spotting to a more obvious flow of blood. Think of it as part of her menstrual cycle. It often slows down mid-cycle.
• Frequent urination: Not always about needing to pee. Sometimes it’s about marking, especially during the fertile stage.
• Tail tucking or flagging: Some dogs tuck their tail to block contact. Others lift it to signal they’re open to mating. It’s instinct, not attitude.
• Flirtier or clingy behavior: She might suddenly want constant attention. Or act flirty around male dogs, even if they’re neutered.
• Restlessness or anxiety: Hormone shifts can make her pace, whine, or seem unsettled.

Basic hygiene tools, like a dog diaper or Mr. Peanut's Naturals Plant-Based Unscented Pet Wipes can make the process easier to manage. If anything feels extreme or if she seems in pain, check in with your vet. Some symptoms can be managed with medication, especially if pregnancy isn’t part of your plan.

How Long Does the Heat Cycle Last and When Is It Officially Over

The canine heat cycle isn’t just about bleeding or behavior shifts. It runs deeper than what you can see. Even when the obvious signs stop, your dog’s body might still be cycling.

Here’s how it breaks down:

• Proestrus (7 to 10 days): This is the start. You’ll likely notice swelling, spotting, and changes in territory marking. Male dogs show interest, but she’s not quite ready to mate.
• Estrus (5 to 14 days): This is the fertile window. Ovulation happens, and the egg is ready. You might see flirty behavior, tail flagging, and more attention to her favorite toy or dog grooming habits. It’s also when pregnancy is possible.
• Diestrus and Anestrus (together take 4 to 6 months): These are the quiet phases. No bleeding. Hormones reset. Her appetite may stabilize. She’s still recovering, especially after her first heat or a recent birth.

The frequency of the cycle depends on the dog, but most go through it every 6 to 8 months. Just don’t assume it’s over when the blood stops. That’s only one part of the dog menstrual cycle.

Dogs can still get pregnant near the end, even if things seem normal. Healthy routines, good dog food, and rest help her bounce back. If anything feels off, talk to your vet before reaching for supplements or medication.

Frequently Asked Questions About Heat Cycle

• How do I know if it’s her first heat? The signs usually look the same as later cycles. Watch for bleeding, mood changes, and shifts in behavior. That’s her body entering the dogs first heat cycle.
• How long will she bleed? Most dogs bleed for 7 to 10 days. But it can be shorter or longer depending on the breed, age, and overall dog health. Keep a dog period diaper or towel handy if she rests on your bed or couch.
• Can I walk her during her heat? Yes. In fact, a little exercise can help. Just avoid off-leash parks or areas with intact males. Stick to short walks and bring a wet wipe for clean-ups if needed.
• Will she be in pain? Not usually. But she might act irritated, restless, or just not herself. Think more mood swings than pain. A quiet space, her favorite blanket, and less stimulation can help.
• Can she get pregnant the first time? Yes. If she’s in estrus, she’s fertile—even during her first cycle. The egg doesn’t care how old she is. It’s ready for reproduction.
• What if she goes into heat more than twice a year? Some dog breeds cycle more often. But if it feels excessive, talk to your vet. Frequent cycles could point to a hormone issue or another underlying animal health concern.

Every dog is different. But understanding the general length, signs, and needs during her cycle makes it easier to care for her without stress.

What to Remember About the Dog Heat Cycle

The canine reproductive system isn’t overly complicated. But it does take some getting used to.

Most dogs go into heat every 6 to 8 months. Some more. Some less. It depends on the dog breed, age, and other factors like progesterone levels or whether she’s had a litter before.

Watch for the signs. Swelling. Discharge. Mood shifts. A sudden obsession with her Bowsers Urban Lounger Dog Bed - Platinum Collection or tail. It’s all part of the process.

Each phase of the cycle plays a role: from the start of bleeding to when she’s no longer fertile. Just because symptoms fade doesn’t mean the cycle is over. Pregnancy is still possible in the later stages.

This isn’t menopause. Dogs don’t stop cycling as they age. But things might change. So, if something feels off or the timing gets weird, call your vet. Disease or hormonal issues aren’t common, but they can happen.

Neutering is an option, but it’s not the only one. What matters most is staying informed and being aware.

You don’t need to be a vet. You just need to pay attention.