The Chihuahua Heat Cycle: Breeding Considerations and Risks

Adrienne is a certified dog trainer, behavior consultant, former veterinarian assistant, and author of "Brain Training for Dogs."

While it is generally easy to determine when an average dog is in heat, Chihuahua owners may face some extra challenges due to this breed's almost obsessive cleanliness. This means that some Chihuahua dog owners may actually miss their Chihuahua's first heat cycle simply because Chihuahuas are fastidiously clean and will lick away any proof of being in heat, explains Caroline Coile, author of The Chihuahua Handbook.

But when do Chihuahuas go into heat exactly? The time they go into heat really varies from one Chihuahua to another. Most likely, however, the first heat will occur any time between the age of six and eight months on average. There are always exceptions, and a Chihuahua going into heat at five months or at one year old is not unheard of. However, being a small breed makes Chihuahuas go into heat much earlier when compared to much larger dog breeds.

Signs Your Chihuahua Is in Heat

Now that you know when Chihuahuas go into heat, you may be wondering how to recognize the signs suggesting it. The Chihuahua's heat cycle duration averages 21 days and includes the proestrus, estrus, and diestrus. The anestrus is basically a mostly inactive rest period. The cycle can be divided into four precise stages, each equipped with distinct features listed below.


This phase lasts anywhere between four to nine days. During this time, your Chihuahua's reproductive tissues may appear puffier than normal. The most evident sign is vaginal bleeding, however, as mentioned earlier, you may barely notice this if you own an overly clean Chihuahua that will lick away any evidence. Male dogs will be quite interested in your Chihuahua, but she will not allow them to mate as of yet.


This phase lasts anywhere between four to thirteen days. The bloody discharge observed in the previous stage will fade out and be replaced by a pink or straw-colored discharge. During this phase, your Chihuahua is officially in ''standing heat'' which means she will stand still with the tail pulled to the side, allowing the male to mount. This is the phase when she is at the peak of her fertility.


Also known as metestrus, this phase basically concludes the active part of the heat cycle and lasts from 60–90 days. Your Chihuahua will no longer be interested in males, even tough some males may initially still stick around. If your Chihuahua is pregnant, this phase lasts until the birth of puppies, 63 days or so later. If your Chihuahua is not pregnant, diestrus may last two to three months, and during this time dogs may experience a false pregnancy.


Anestrus is simply the phase during which the reproductive organs get to rest. It typically lasts between two and three months. While this sounds much like an inactive quiet time, in reality, your Chihuahua's pituitary glands and ovaries are getting ready for the next proestrus phase, several months ahead. Consider that Chihuahuas generally go in heat once every five to eight months, so this means your Chihuahua will most likely go in heat twice a year.

Learning when Chihuahuas go into heat is fundamental for any average dog owner or prospective breeder. If you are a dog owner, you must secure your Chihuahua and keep her safely away from intact males. If you are planning on breeding your Chihuahua, you must determine the best time to breed in order to heighten the chances of pregnancy. However, it is imperative to research and learn to be a reputable Chihuahua breeder after reading the important considerations pertaining to breeding Chihuahuas.

How to Care for a Chihuahua in Heat

Upon recognizing the signs of heat, you must do what you can to protect your Chihuahua from the attention of males if you are not planning on breeding. If you are still having a hard time deciphering the potential signs of heat, rest assured, the behavior of intact male dogs will let you know. Do not be surprised if male dogs will show up on your doorstep. According to the American Kennel Club, a male dog is capable of detecting the scent of a dog in estrus up to five miles away!

As a responsible dog owner, you must do as much as you can to keep your Chihuahua away from males. Avoid the dog park, and if you must take her out, have her leashed at all times. Never underestimate the persistence and determination of intact male dogs. They can be quite creative and use astute planning to dig under or even climb over a fence to get to her. Also, watch the door: even though escaping has never crossed your Chihuahua's mind, when in heat, roaming is more than a mere possibility.

Preventing your Chihuahua from urinating all over the place will also keep males at bay since females urinate quite frequently during their heat cycle simply to leave ''calling cards'' denoting their availability. The urination may not be isolated to the indoors; in fact, some female dogs will have no problem urinating in the home. And just in case you were wondering about how to protect your furniture and carpet from that bloody discharge, you can invest in a pair of britches, special panties for dogs in heat.

If all the above sounds like too much work, consider spaying your Chihuahua. Spaying is behaviorally and medically beneficial for your dog in many ways, and will solve the problem of unwanted puppies, reducing the enormous burden of pet overpopulation. The ASPCA claims that millions of healthy dogs and cats are put to death each year in the United States just because there are not enough homes for them.

Tips and Risk Factors of Breeding Chihuahuas

When do chihuahuas go into heat? The answer to this question is particularly important if you are planning to breed your Chihuahua, therefore you must do your homework well to heighten the chances of getting her pregnant. Whether you are planning to breed her naturally, or resort to artificial insemination, you need to figure out the days she is most fertile.

In natural breedings, male dogs simply know when the right time is, and females will stand for them. Generally, this happens between the 8th and the 15th day of heat counting from the day your Chihuahua started bleeding, explains veterinarian Margareth V. Root Kustritz with the University of Minnesota. There are really no guarantees that mating in these days will result in puppies. However, breeders have found that allowing breeding every other day starting from the 7th day of heat up until the female allows it, heightens the chances of success.

If you are artificially inseminating and need to figure out the most fertile days, your veterinarian may help by assessing cells collected from a vaginal swab or by measuring the levels of progesterone in the blood. Ideally, the artificial insemination should be performed twice, two and four days after ovulation, further explains Margareth V. Root Kustritz.

Regardless, of how you intend to mate your dog, breeding is a serious choice, especially when it comes to a breed such as a Chihuahua which has a far more risky pregnancy compared to other larger breeds, explains Marli Medinnus, a professional breeder of AKC Longcoat Chihuahuas in San Jose, California.

Chihuahuas should never be bred on their first heat. They are too young and giving birth may lead to complications. They should be bred instead for the first time during their second or third heat, and before turning three years old. Your Chihuahua should also have the right conformation with a wide pelvic area and a good tuck up in order to heighten the chances of carrying and delivering the pups safely.

Breeding is something that requires a lot of expertise with a good amount of knowledge about genetics and ultimate goals about improving the breed in mind. Costs must also be evaluated, since Chihuahuas are prone to requiring Cesarean sections, not to mention expenses associated with testing breeding stock for heritable defects and genetic diseases.

Shots, x-rays, puppy shots, and other unexpected medical treatments are more expenses that must be added to the list. But there is much more than that. If this sounds like a lot of work, your best bet is to spay your Chihuahua and allow her to live her life to the fullest since breeding can also considerably shorten her expected life span.

For Further Reading

  • How to Keep Male Dogs Away From Females in Heat
    When your female dog is in heat expect all your neighborhood intact male dogs to know. No, in the canine world there are no needs to join websites like or to read through romantic classified ads to find love. The news simply travels...
  • All about dog pregnancy
    After your beloved dog has been matched with a handsome stud and successfully bred, the 63 day countdown has begun. A mix of emotions pour over you, of course, lots of excitement but also bits of anxiety as this is the first dog you own to be...
  • Signs your dog is pregnant
    When it comes to canine pregnancy there are two different types of owners: the
  • The Dog's Heat Cycle Explained
    A dog's heat cycle may appear to be something quite difficult to understand. Unlike other species, the heat cycle of canines does not seem to follow any logic such as following a specific seasonality or...

Questions & Answers

Question: Why is my dog's blood almost white?

Answer: If you are seeing a clear water-like discharge, this can be indicative of several things going on. It may be that she is close to nearing the end of her heat cycle or it can be due to her being pregnant. However, if it is white rather than clear, it may be concerning as it can be a sign of a bacterial infection and possibly pyometra. Pyometra is a serious infection of the uterus and is seen in dogs after their heat cycle. This condition can become life threatening, so best to play it safe and see your vet.

Question: What are the heat signs in males?

Answer: Male dogs do not go into heat as female dogs do. They respond to smells emitted by female dogs in heat.

Suzanna on April 14, 2019:

I had a male chihuahua. But once he got in heat. He didn't want sleep in the house. On Tuesday morning he was no where to be found. His been missing since 4-9-19. I been crying all week. I miss him so much. My other dog misses him too. It's been real hard.

Tonya on February 25, 2019:

Hi I have a Chihuahua mix female and male. The male is fixed the female is not. She's in heat and the male ended up mounting her and they got stick together for a few and now the female won't eat and is just laying around shaking and panting and keeps crying out making a loud screeching noise. I am very concerned bout what could be wrong with her . Any ideas?

Jackie on January 24, 2019:

My female Chihuahua went into her 1st heat Nov.2017 so we found a stud but she has not gone into her 2nd heat & it's now Jan. 2019. What is wrong, what should I do? She turned 2 in October. 2018. Am I doing something wrong? We are together 24/7 she goes everywhere I go until last Dec 7th, 2018 I broke my hip & had to have 3 surgeries. Could it be that she was stressed out & could that be why? Also she humps her stuffed animals is that play or a sign?

Adrienne Farricelli (author) on October 19, 2017:

Dusti I would check with your vet just to be sure there are several reasons that may cause male dogs to be attracted such as urinary tract infections or anal gland problems.

Dusti on October 15, 2017:

My chihuahua gave birth 8 weeks ago

Is it possible for her to go into heat again this soon?

My male dogs are trying to get her again so I was just wondering

Adrienne Farricelli (author) on October 09, 2017:

You need to contact your vet if she's not producing puppies, Chihuahuas (especially the apple head variety) need C-sections.

Leana on October 08, 2017:

Ok I have a Chihuahua and she has lost her plug and is in labor ,she s patting and pushing and she has been puking also is that normal and she hasn't had a puppy yet ,it seem like she's might be struggling how do I know now if she is ,she also keeps moveing around alot she won't stay in one spot

Shawna on May 20, 2017:

I have a 7 year old chihuahua and my male chihuahua got stuck with my female is my female to old to have puppies and if she can have puppies how many times should I let the mount

Shawna on May 20, 2017:

My Chihuahua is 7 years old do u think she's to old to have puppies

Janie Carmichael on January 28, 2017:

I have a 1 1/2 yr old female that has successfully "connected" with my 7 month old male twice today. Is it too early for impregnation?

Adrienne Farricelli (author) on November 24, 2016:

Being in heat that long is concerning. Please see your vet.

Debbie on September 19, 2016:

My dog is 14 yrs old and has been in heat for 2 months why and what can I do she is to old to have baby's and I don't think she would make it through surgery to get her fixed

Joedii on June 25, 2016:

Our chihuahua is on heat at 9mos when i get her the they said she already once and this her 2nd heat. Its is okay now to breed her?

Michelle on April 01, 2016:

Very important not to let her get pregnant in her first season which lasts usually 3 week

Ruben Garcia on March 23, 2016:

Hello, i came home a few hours ago and noticed my female chihuahua was bleeding. I decided to separate her from my other chihuahua (a male). She is going to be 7 months and this is her first heat cycle. Is it safer to keep her separated from him ? If so, for how long?

Adrienne Farricelli (author) on May 03, 2015:

Male dogs so not go in heat, only females do. So if your male dog is acting odd it could be there's a female dog in heat somewhere nearby that he is responding to.

dominga Camacho on May 02, 2015:

How can I take care of my male dog on heat

Chihuahua Genetics And Common Health Problems

Thankfully, Chihuahuas in general d o not have common health issues, but there is still a risk of some common genetic abnormalities that might appear. Low blood sugar is a common issue for smaller dogs in general, so regular feedings are essential.

Additionally, Chihuahuas run a risk for heart issues like heart murmurs or pulmonic stenosis. These would most likely not appear until the dog is older or if the dog is over-exercised. It m ight require a special diet and fitness schedule to keep your dog as healthy as possible.

There are also risks of hydrocephalus and open fontanel, both of which have to do with brain development. These dogs need extra care and to be protected from injuries to the head.

Finally, they do have a risk of patellar luxation, which is when the leg bones are not properly aligned. This is usually visible at birth. Sometimes it resolves itself and other times, surgery is required.

Pyometra and cystic endometrial hyperplasia are both uterine diseases. The conditions are related to hormonal changes, usually after a heat cycle. Bacteria, especially E. coli, grow rapidly as the lining thickens. This can cause a life-threatening infection. Many veterinarians compare pyometra and cystic endometrial hyperplasia to acute appendicitis in humans. If an afflicted dog doesn't have her uterus removed immediately, the infection is usually fatal.

Non-spayed Chihuahuas are at risk of developing uterine and mammary cancer, especially as they get older. If a puppy is spayed before her first heat, her risk of these types of cancers is almost completely eliminated. Uterine and mammary cancer are treatable when detected early, but often they are not diagnosed until after the cancer has spread to other organs and has become life-threatening.

Dog Breeding for Beginners: What You Should Know

Planning a litter of puppies? Margaret V. Root Kustritz, DVM, Ph.D, DACT, professor of small animal reproduction at the University of Minnesota, answers frequently asked questions from breeders preparing to breed that promising next litter.

How Often Do Dogs Go Into Heat?

Bitches should have an obvious heat cycle by 24 months of age. Although bitches vary in the frequency of their heat cycles, an average female goes through heat about every seven months. A bitch is not considered abnormal unless she has not had an obvious heat cycle for one year.

Is It Okay to Breed a Bitch in Back-to-Back Heat Seasons?

That depends on how many puppies she whelped the first season and how well she maintained her body condition during pregnancy, whelping, and lactation. If she had several puppies and was thin by the time they were weaned, she probably cannot regain normal body condition before she is in heat again and thus should not be bred. If she had few puppies at the first breeding and is in excellent body condition, she potentially could be bred again. Every circumstance and every bitch should be evaluated individually.

What Do You Feed a Pregnant Dog?

A growth or performance food, like Purina® Pro Plan® SPORT 30/20, is best to feed a pregnant bitch because they are nutrient dense and thus require less food to sustain her increasing energy needs. Particularly later in the pregnancy when her uterus takes up much of the space of the abdomen, she may have trouble eating a significant amount of food. At whelping, a bitch should weigh 5-to-10 percent more than before breeding. Try to avoid obesity as it is associated with difficulty whelping, increased birth defects in neonates, and stillbirths. Likewise, a thin body condition can cause conception failure, loss of pregnancy, and low-weight pups.

How Soon Should Puppies Nurse After Birth?

Puppies cannot make their own antibodies at birth, so it is important that they receive their dam’s first milk, colostrum, which is rich in disease-protecting antibodies. Puppies can absorb these antibodies from their intestinal tract for only about the first 24 hours of life. Don’t be concerned if your bitch does not nurse until all the puppies are born. This is common behavior that generally causes no risk to puppies.

What Causes Small Litters?

The most likely culprit is breeding at the wrong time. The optimal breeding day for litter size is two days post-ovulation, as determined by your veterinarian based on progesterone measurements. Other possible causes of small litters are hypothyroidism, uterine infection, and advanced age of the bitch.

Was the Runt Conceived Later Than His Littermates?

Probably not. Runt puppies most likely are the same age as their littermates but had poor placentation. Bitches release all their eggs over a 24-hour span. Even if the conception of that small pup occurred later than conception of the other puppies, all pups float around free for 17 days before implantation and formation of the placenta.

How to Prevent Your Dog From Going Into Heat

The only option to prevent your dog from going into heat is to have her spayed. Spaying is highly recommended for all female dogs unless you plan on strengthening the breed. Once your dog is spayed, she will have a reduced risk for mammary cancer and will be unable to contract uterine infections or go through a heat cycle.  

You can have your dog spayed while she is going through her heat, but the surgery is more complex. Speak with your veterinarian about the best time to spay your pet.

Watch the video: Dog Breeding Back to Back. Unethical, Unwise, Sensible? The Good,The Bad u0026 The Ugly! (October 2021).

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