How To Know If My Dog Is in Heat Season?

Recognizing the signs of heat in female dogs is essential for maintaining their health and preventing unwanted litters. Below is a detailed guide covering physical indicators, behavioral changes, the four stages of the heat cycle, and essential care recommendations.

Understanding the Canine Heat Cycle

Female dogs go through a natural reproductive pattern known as the estrus cycle, which includes:

1. Proestrus – Beginning signs of heat
   

2. Estrus – Fertile stage
   

3. Diestrus – Post-fertile period
   

4. Anestrus – Resting phase until next cycle
   

Most dogs enter their first heat between six and twelve months. Smaller breeds may start earlier, while larger breeds may begin later.

According to veterinary experts summarized by PetMD, a typical heat cycle lasts around two to four weeks, beginning with swelling of the vulva and bloody discharge that gradually becomes lighter as the dog enters the fertile stage.

This aligns with what most pet owners observe during their dog’s reproductive cycles.

Signs Your Dog Is in Proestrus (Beginning of Heat)

Proestrus usually lasts 7–10 days.

Physical Signs

• Swollen vulva
  

• Bloody discharge
  

• Frequent licking of genital area
  

Behavior Changes

• Restlessness
  

• Increase in affection or mild irritability
  

• Avoiding males despite attracting them
  

Dogs are not fertile during this stage.

Signs of Estrus (Fertile Stage)

Estrus lasts 5–14 days, and this is when pregnancy can occur.

Physical Signs

• Discharge becomes lighter, often straw-colored
  

• Vulva softens
  

• Strong scent that draws male dogs from far distances
  

Behavior Changes

• Tail “flagging” or moving aside
  

• Seeking attention from male dogs
  

• Frequent marking and urination
  

This is the peak breeding window.

Recognizing Diestrus (End of Heat)

Diestrus lasts around two months and marks the end of fertility.

Diestrus Signs

• Discharge stops
  

• Vulva reduces to normal size
  

• Calm, stable behavior
  

• Reduced interest in male dogs
  

Some dogs may show signs of a false pregnancy, which PetMD also notes can occur from natural hormonal changes.

Anestrus (Resting Phase)

This stage lasts 3–6 months, depending on breed. No heat symptoms occur during this time.

Major Indicators Your Dog Is Entering Heat

1. Swollen Vulva

A noticeable enlargement is one of the earliest and most reliable signs.

2. Vaginal Discharge

Color changes throughout the cycle:

• Red/Bloody → Proestrus
  

• Light/Pale → Estrus
  

• None → Diestrus
  

3. Behavioral Changes

• Excessive marking
  

• Restlessness or mood shifts
  

• Attempts to escape or seek males
  

4. Attraction of Male Dogs

Male dogs may become very focused or congregate around your home.

How Long Do Dogs Stay in Heat?

Most dogs stay in heat for 2–4 weeks, depending on size and breed.

How Often Do Dogs Go Into Heat?

Most dogs cycle every six months. Small breeds may cycle more frequently, while large breeds may only cycle once a year.

How to Care for a Dog in Heat

1. Keep Supervised at All Times

Prevent contact with unneutered male dogs.

2. Use Heat-Specific Dog Diapers

Helps contain discharge and maintain cleanliness.

3. Maintain Hygiene

Clean bedding daily and gently wipe the genital area to reduce odor.

4. Provide a Calm Environment

Hormonal changes can increase sensitivity and stress.

Spaying Considerations

Spaying offers significant medical and behavioral benefits:

• Reduced risk of mammary tumors
  

• Prevention of pyometra, a serious uterine infection
  

• Eliminates unwanted pregnancies
  

Consult a veterinarian for proper timing. Many vets recommend spaying after the first heat, though timing varies by breed.

When to Contact a Veterinarian

Seek medical attention if your dog shows:

• Excessive bleeding
  

• Foul-smelling discharge
  

• Severe lethargy or vomiting
  

• Very frequent or very rare heat cycles
  

These may indicate underlying reproductive disorders.

Frequently Asked Questions (FAQ)

1. How old are dogs when they first go into heat?

Most experience their first cycle at 6–12 months.

2. How often do dogs go into heat?

Typically every six months.

3. How long does a dog stay in heat?

Usually 2–4 weeks.

4. Can a dog get pregnant during her first heat?

Yes. Dogs are fertile during their first estrus cycle.

5. What are the earliest signs of heat?

Swollen vulva and bloody discharge.

6. Should I walk my dog while she’s in heat?

Yes, but avoid dog parks or areas with loose dogs.

7. Why do male dogs suddenly appear near my home?

Your dog is releasing pheromones that signal fertility.

8. Can spaying stop heat cycles permanently?

Yes, spaying removes the organs that produce heat hormones.

9. Can dogs experience mood changes during heat?

Yes, hormonal shifts can cause irritability or clinginess.

10. What products help most during heat?

Dog diapers, calming supplements, washable bedding, and enzyme cleaners.