You may be wondering what to expect during your Chihuahua’s heat or how to tell they’re having one. Don’t worry. You’ve come to the right place! We cover a lot of information for you in this article.

An adult Chihuahua which is not spayed will have regular yearly heat cycles. A new Chihuahua parent who’s never experienced a dog in heat, it can be not very clear to determine exactly when your little Chihuahua is in heat.

What Does it Mean When a Chihuahua Goes Into Heat?

A “heat” refers to a stage in the female dog’s reproductive cycle. She is the stage in which the dog is ready to be bred.

There are several signs to watch to determine if your Chihuahua is in heat.

Your Chihuahua may not experience all of these, or they may not be obvious to detect, but she will likely encounter most of them.

Signs your Chihuahua is in heat include:

  • A swollen vulva
  • Vaginal bloody discharge
  • More frequent urination
  • Changes in behavior (more friendly, more reactive/aggressive, etc.)
  • “Flagging” – a sideways lift of the tail
  • Other dogs may have behavior changes around your female
  • Changes in appetite

How Often Does a Chihuahua Have a Heat Cycle?

Like people, every Chihuahua is different. However, most Chihuahuas experience a heat cycle every six months or nine months—most heat cycles in dogs last about a month – 21 to 28 days, to be exact.

Chihuahuas have their first heat cycle young. As a six months old and as late as one and a half years old. Often you can predict when your Chihuahua’s first heat cycle will occur by relatives (when did littermates, their mother, and other relatives have their first heat?).

Stages of a Chihuahua’s Heat Cycle

There are three stages in a dog’s heat cycle. Regardless of the breed of dog…all dogs experience these same three stages.

Stage one:
During the first stage of your Chihuahua’s heat cycle, her vulva will swell and look more significant than usual.

In this stage, your Chihuahua may urinate more often with a bloody vaginal discharge.

She will hold her tail close to her body as a sign that she’s uninterested in breeding.

You also may notice an increase in grooming behaviors. This increase in grooming behaviors can often be why people miss the early signs of their dog’s heat cycle as the dog is cleaning up any apparent discharge.

Stage two:


This stage is when your Chihuahua is ready to breed.

Her vaginal discharge will turn from bloody to a brownish or clear discharge.

She may also start “flagging” her tail, which means holding it at an odd angle to the side.

Now is the time to consult your veterinarian if you want to breed your dog*. Your veterinarian should be able to provide blood testing that will help you determine the correct timing.

*NOTE:  breeding small dogs can be very dangerous. Pregnancies, in general, come with many risks. But small dogs have been known to have complicated pregnancies. They deliver due to the size of the puppies compared to the size of the mother. You should be financially prepared for emergencies, including cesarian. If you are unprepared for such emergencies, there is a chance of losing the puppies and the mother.

During this second stage, your Chihuahua will be giving off pheromones that male dogs will be able to smell miles away. So, you must keep your dog secure to prevent unplanned pregnancies, as unaltered male dogs have been known to scale fences or sneak into homes to get to the in-heat female.

Third and final stage:

The last step of your Chihuahua’s heat cycle is called diestrus.

During this stage, your Chihuahua will no longer be interested in breeding.

Vaginal discharge will cease, and her vulva will return to its standard size.

Even if you did not breed your Chihuahua, she may show signs of “false pregnancy” during this time and even long after the entire heat cycle ends.

What is a False Pregnancy?

After your Chihuahua completes her entire heat cycle, her brain may tell her body that she is pregnant, even though she’s not. This is more common if you have other dogs in your home…even if the other dogs are spayed or neutered.

Symptoms of false pregnancy can include:

  • Nesting
  • Restlessness
  • Depression
  • Lethargy or deficient energy
  • Low appetite
  • Swollen breasts
  • Mammary gland secretions

Most false pregnancies are mild, and symptoms subside within a month. However, if your dog appears physically ill or behavioral changes are concerning, do not hesitate to contact your veterinarian. There are conditions related to un-spayed females that can be lethal (we go more in-depth on this later in this article).

How Do I Know When My Female Chihuahua is in Heat Pin

How to Manage Your Chihuahua’s Heat

There are several things to remember when your Chihuahua is in heat. Here are some of the important ones:

  1. You’ll likely need to keep your Chihuahua away from other dogs when she’s in heat. Female-on-female aggression is common, but it’s essential to ensure that males (exceptionally intact ones) cannot get to her. Don’t leave your Chihuahua in the yard unattended, and make sure she cannot escape. Most dog parks prohibit female dogs in heat from visiting, but it’s a poor idea to try and take yours regardless because the hormones and scent from your female can cause behavioral issues in other dogs even if they are fixed.
  2. Since there will be vaginal discharge when your Chihuahua is in heat, you may want to consider doggie diapers. We recommend adding panty liners as inserts to the diapers to increase absorbency and cut down on messes (and washes). Diapers can help keep the clutter contained rather than on your floors and furniture. Remember, though, that diapers may not always be the best choice because it may be hard to find diapers that fit correctly and stay on, and your Chihuahua won’t be able to clean herself or go potty while wearing them. If you opt not to use diapers, you can use old blankets to cover your bed and furniture to protect them from your Chihuahua’s vaginal discharge. That way, cleaning up after your girl is easy, and your good blankets and furniture won’t get ruined.
  3. If your Chihuahua has lost her appetite, try adding chicken or baby food to her meals, and these will help entice her to eat while not adding many calories to her correct diet.

A Warning If Choose to Keep Your Chihuahua Intact:

Even if you never breed your Chihuahua, a fatal condition can occur during or after a dog’s heat called Pyometra. This is when the uterus becomes infected. There are two types of Pyometra. Open Pyometra, in which case there will be a puss-like discharge from the vulva, and Closed Pyometra, in which case there will not be any discharge as it is contained within the uterus. Either way, Pyometra is lethal, and you’ll need to rush your Chihuahua to the vet immediately.

Again, this is an emergency that can ultimately lead to death, so always be on the lookout for signs and symptoms of Pyometra.

For many reasons, keeping a close eye on your Chihuahua when she’s in heat is essential.

Some people find a female dog’s heat cycle stressful and turbulent time in the household.

Many people do not want to deal with the stress and needed lifestyle changes of a female dog in heat.

They also may not like having to keep their dog in the house for an entire month twice a year or the extra precautions needed if venturing out into public with a female dog that is in heat.

If you feel you would rather not have to worry about all the challenges above of your Chihuahua in heat, there are options for you (keep reading).

How to Prevent a Chihuahua From Going Into Heat

The only way to eliminate a female dog’s heat cycles is to get them spayed.

Spaying a dog involves removing a female dog’s uterus and ovaries*, thus eliminating heat cycles.

*Note:  there is a procedure called OSS (Ovary Sparing Spay), which removes the ability to reproduce but leaves one or both ovaries intact. This would be something to discuss further with your veterinarian if you are concerned about hormone loss for your Chihuahua. Also, not all veterinarians perform the OSS surgery.

Many scientific studies recommend keeping your female dog intact until its growth plates are closed. The studies state that it allows them to reap the benefits of the hormones they were born with and can help them be healthier throughout their lifetime.

However, if you cannot keep your dog intact through their first heat, that’s okay. There are far fewer risks with an early (pre-six-month-old spay) that with an unplanned or even a planned pregnancy for Chihuahuas.

If you purchased your Chihuahua, your veterinarian (and breeder) would help you come up with the best time to spay your Chihuahua.

If you choose to wait until your Chihuahua’s growth plates are closed, that likely means that you will likely experience at least one heat with your female Chihuahua before they are spayed. Remember that it takes roughly three months for your Chihuahua’s hormones to return to a normal state following a heat cycle. Therefore, we recommend you do not spay your Chihuahua until at least three months after her process.

Essential Things to Remember about Your Chihuahua’s Heat Cycle

Your Chihuahua will inevitably have heat cycles unless she is spayed.

While a swollen vulva and discharge are the most obvious symptoms, there are several other signs to consider.

Your Chihuahua’s safety and health are a priority, so consult your veterinarian with specific questions and concerns related to your furry friend’s heat cycle.

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