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Chihuahua First Heat and Cycle: What To Expect and When

Last Updated: December 17, 2023

Chihuahuas are tiny but undergo phases similar to every other breed. What’s tricky about a Chihuahua is their reproduction aspect. From experiencing the first heat to producing offspring, several scenarios need your attention. So, what’s the first heat and cycle of a Chihuahua like?

Your Chihuahua will likely enter her first heat between six to eight months of age, although it can vary from dog to dog. The duration of the heat cycle is typically about three weeks. During this time, you may notice various physical and behavioral changes, such as a swollen vulva, a bloody discharge, and more frequent urination.

Knowing these signs can help you support your Chihuahua during this challenging time. But that’s not everything. The first heat of a Chihuahua is categorized into several stages.

In my experience rescuing several breeds, I’ve noticed that small breeds need more attention and are also vulnerable to unusual complications as soon as they enter the heat period.

If you have a Chihuahua, you shouldn’t skip this article that can change your care plan for your little one. Let’s get started!

Chihuahua First Heat and Cycle

What Does Chihuahua Heat Cycle Mean?

The heat cycle refers to the female Chihuahua’s reproductive cycle, which typically occurs twice a year. This cycle prepares her body to conceive and bear offspring. To understand the Chihuahua heat cycle, let’s discuss the four stages: Proestrus, Estrus, Diestrus, and Anestrus.

Proestrus Stage

During the Proestrus stage, your Chihuahua’s body is preparing for mating. You may notice swelling in her vulva and some bloody discharge. This phase generally lasts for a week or slightly longer. Your Chihuahua might also show signs of restlessness, which is expected during this time. The East Central Veterinary Hospital recommends extra attention to changes in body language.

Estrus Stage

Next is the Estrus stage, where your Chihuahua is fertile and ready to mate. The bloody discharge will turn into a lighter color, such as pink or yellow. This stage lasts for approximately 5 to 9 days, and you’ll notice that your Chihuahua becomes more receptive to male dogs during this period.

Diestrus Stage

Following the Estrus stage is Diestrus, which lasts for around two months. During this phase, your Chihuahua’s body begins to return to normal. If fertilization occurs, she’ll experience pregnancy. If not, her hormone levels will gradually return to their non-heat state.

Anestrus Stage

Lastly, the Anestrus stage is when your Chihuahua’s reproductive system takes a break. It typically lasts for 4 to 5 months, and during this phase, there are no signs of the heat cycle. Your Chihuahua’s body uses this time to prepare for the next cycle, starting with the Proestrus stage once again.

“Without knowing these stages, you can’t give the right quality of care. Get yourself acquainted to it! Your Chihuahua will thank you!”

Pregnant Chihuahua
Pregnant Chihuahua

When Do Chihuahuas Come Into Heat?

Chihuahuas typically experience their first heat between the ages of 6 and 10 months. Keep in mind that this timeframe can vary, with some entering heat earlier or even later, up to 16 months of age. Like humans, each dog is unique and may develop at different rates.

If it’s the first heat of your Chihuahua or if your little one is nearing the timeframe, here’s a free calculator to use:

Dog Heat Cycle Calculator

During their first heat, most female Chihuahuas will exhibit signs of puberty. These signs could include swelling of the vulva, a slight bloody discharge, and increased affectionate behavior toward other dogs.

When my Chihuahua had her first heat, I noticed she was more clingy than usual. I made sure to keep her comfortable and safe by providing her with a cozy space to rest and use doggy diapers to minimize mess.

Wondering when the heat cycle comes to an end? Check this: At what age do female dogs stop having heat cycles?

How Do You Know When Your Chihuahua Is In Heat?

A dog entering a heat phase is probably the most critical period. You’ll never know if your Chihuahua is in pain or is just experiencing regular physical symptoms of estrus if you don’t know the basics.

“If you’re a new pet parent, I’d strongly recommend keeping a list of physical signs handy. I did something similar when my dog had her first heat.”

One of the first physical signs to look for when your Chihuahua enters heat is a swollen vulva. This can be very noticeable and might cause concern if you’re witnessing it for the first time. For your Chihuahua, this is simply a normal part of the heat cycle.

In addition to a swollen vulva, your Chihuahua may experience behavioral changes. She might become more agitated, restless, or nervous during this period.

On the other hand, WebMD mentions how certain Chihuahuas can exhibit contrary symptoms like extreme friendliness, hunting for male dogs around, and frequent mounting behaviors.

You might also notice an increase in bleeding from the vulva, which can range from slight to significant. The discharge can be bloody or straw-colored, indicating that your Chihuahua is experiencing her heat cycle.

Another sign to watch for is flagging, where your Chihuahua lifts her tail to other dogs, signaling her willingness to mate. This behavior typically goes hand-in-hand with other signs, such as increased urination and abdominal discomfort.

By being aware of these physical signs and behavioral changes, you can better understand when your Chihuahua is in heat and provide her with the necessary care and attention.

But, if you need a visual representation to understand what goes on within the physical system of a Chihuahua, I encourage you to watch this helpful video.

How To Care for a Chihuahua In Heat

When your Chihuahua comes into heat, you must ensure her comfort and safety. Here are some tips to help care for your Chihuahua during this time.

First, provide your Chihuahua with a comfortable and quiet space to rest. She may display nesting behavior, so offer her extra blankets or a designated dog bed. Ensure her eating and drinking areas are easily accessible, as her appetite may decrease or increase during this period.

Pro Tip! Consider using dog diapers to help manage any discharge and keep your home clean. Various doggie diaper options are available, but choose one that fits your Chihuahua comfortably and securely.

You can purchase diapers for your dog here:


Before letting your Chihuahua wear a diaper, read this: How long can a dog wear a diaper in heat?

Regular exercise is still essential during a Chihuahua’s heat cycle. Keep her on a leash when walking to prevent any unwanted encounters with male dogs. Be cautious, as she might be more irritable or defensive than usual during this time.

How Often Do Chihuahuas Go Into Heat?


Chihuahuas typically experience their first heat cycle between 6 and 10 months of age. However, be mindful that the timing may vary. Some Chihuahuas might have their first heat slightly earlier or later, even up to 16 months of age. After the initial heat, your Chihuahua will settle into a more regular reproductive pattern.


As happens in humans, gestation delays menstrual periods and fertility seasons. Similarly, the interestrus interval, or the period between estrus seasons, is prolonged in Chihuahuas and other dogs after whelping. 

Chihuahua First Heat


Unlike some breeds with well-defined breeding seasons, Chihuahuas don’t exhibit a strong correlation between their heat cycles and specific times of the year. While outdoor temperatures or daylight changes might have minimal influence, Chihuahuas’ heat cycles mainly depend on individual factors, such as age and genetics.

As such, be prepared to manage your dog’s estrus cycles anytime throughout the year.

Should I Spay My Chihuahua?

Spaying your Chihuahua offers numerous health benefits. Contrary to widespread belief, waiting until your female Chi has gone through her first heat cycle before spaying may NOT be best. This is something specific to the individual dog that warrants a conversation with your vet.

By spaying your dog before her first heat cycle, you can help to prevent diseases of the reproductive system, such as pyometra and mammary cancer. In addition, spaying eliminates the heat cycles, making life easier for both you and your furry friend.

According to American Veterinary Medical Association, early spaying reduces the probability of breast cancer, uterine infections, and other issues associated with the reproductive system.

Keep in mind that there are risks associated with any surgery. However, these risks are generally low when a qualified veterinarian performs the procedure.

Do you want to know if your little furry friend is ready for a spay procedure? Reach out to a vet who will conduct a blood test and examine the overall health.


When does a Chihuahua go into heat for the first time?

Your Chihuahua will likely experience her first heat between six and eight months of age. However, the timing can vary, with some dogs entering heat as early as five months or as late as one year old. In general, smaller breeds tend to reach puberty earlier than large breeds.

What are the signs of a Chihuahua in heat?

Some common signs of heat in a Chihuahua include a swollen vulva, bloody discharge, frequent urination, excessive licking, mood swings, and heightened interest from male dogs. Your dog may also become anxious or aggressive due to hormonal changes.

How long does the fertile period last in a Chihuahua’s heat cycle?

The fertile period, or estrus stage, is when your Chihuahua is receptive to mating and is most likely to become pregnant. This stage generally lasts 7-10 days and is important to monitor closely if you’re planning to breed or want to prevent an unwanted litter of puppies.

How do I know when my Chihuahua is ready to breed?

A Chihuahua is typically ready to breed after her third heat cycle. This ensures her reproductive system is fully matured and reduces the risk of complications during pregnancy. Breeding can occur when she displays signs of heat, such as a swollen vulva and discharge, and shows interest in the male.

Read more: Chihuahua Breeding Age: A Key Guide for Healthy Pups

Can I bathe my Chihuahua during their heat cycle?

Yes, you can bathe your Chihuahua during her heat cycle. Use lukewarm water and mild shampoo, but avoid getting water inside her ears or near the vulva. Dry them thoroughly and keep her warm after the bath.

Sowmya Sankaran
Sowmya Sankaran is crazy about dogs, rabbits and birds! An avid rescuer and rehabilitator of dogs and other animals, she runs the Life With Equality Charitable Trust, an animal shelter in Chennai, India. She is also the founder of Petsmond, a pet website, in which she shares her experiences in raising different creatures and paying attention to intricate aspects of their health.

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