If you’re a first-time dog owner or have recently adopted a female dog, you might be surprised to notice bleeding or changes in behavior and wonder, “Do female dogs have periods?” The answer is yes — but it’s different from the human menstrual cycle. Understanding what’s normal during a female dog’s heat cycle, and when to seek veterinary care, is essential for your pet’s health and your peace of mind.
Do Female Dogs Have Periods?
Technically, female dogs do not menstruate in the same way humans do. Instead, they go into estrus, also known as being in heat. This is a phase in the reproductive cycle when the dog becomes fertile and may exhibit vaginal bleeding, behavioral changes, and physical symptoms.
Female dogs typically have their first heat cycle between 6 and 24 months of age, depending on their breed and size. Small breeds tend to start earlier, while larger breeds may begin later.
The Four Stages of the Canine Heat Cycle
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Proestrus
Duration: 7–10 days
Symptoms: Swelling of the vulva, bloody discharge, increased urination, behavioral changes
This is the stage most often confused with a “period.” However, it’s part of the preparation for mating. -
Estrus
Duration: 5–10 days
Symptoms: Discharge lightens to pink or straw-colored, female is receptive to males
This is the fertile period where conception can occur. -
Diestrus
Duration: 2 months
The body returns to normal if no pregnancy occurs. Hormonal changes continue regardless of mating. -
Anestrus
Duration: 2–6 months
The resting phase before the next cycle.
What’s Normal During a Dog’s “Period”?
During proestrus and estrus, it is normal for your female dog to:
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Experience bloody vaginal discharge
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Have a swollen vulva
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Be more affectionate or clingy
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Lick herself frequently to stay clean
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Attract interest from male dogs
Most of the time, these symptoms are not cause for concern and are simply part of the natural reproductive cycle.
When to Worry: Signs of a Problem
While mild bleeding and behavior changes are normal, there are some warning signs that should prompt a veterinary visit:
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Excessive or prolonged bleeding (lasting more than 2–3 weeks)
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Discharge with a foul odor
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Lethargy or loss of appetite
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Vomiting or fever
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Bleeding in a spayed dog (this is abnormal and may indicate a serious issue like ovarian remnant syndrome or tumors)
If you suspect anything unusual, consult a vet immediately.
Spaying: A Responsible Choice
Spaying (ovariohysterectomy) is the surgical removal of a dog’s reproductive organs and eliminates future heat cycles and periods. Spaying:
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Prevents unwanted pregnancies
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Reduces the risk of mammary tumors and uterine infections (like pyometra)
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Helps manage behavioral issues related to hormonal fluctuations
Veterinarians often recommend spaying around 6 months of age, though this may vary depending on your dog’s size and health.
Final Thoughts
Yes, female dogs do have periods — but it’s part of the estrous cycle, not menstruation as humans experience it. Mild bleeding, vulva swelling, and behavioral changes are normal signs of heat. However, if your dog experiences symptoms that seem extreme or unusual, it’s important to consult your veterinarian.
Knowing what to expect during your dog’s cycle and when to take action will help keep her healthy and reduce stress for both of you.
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