When Do Boston Terriers Go Into Heat?

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Similar to humans, Boston Terriers also undergo a reproductive cycle that makes them receptive to mating. If you’re wondering when Boston Terriers go into heat, I’ll look at how heating happens so you can plan breeding, spaying, or neutering times. 

When Do Boston Terriers Go Into Heat? 

Boston Terriers reach puberty and sexual maturity around 6 to 8 months. Around this time, Boston Terriers will experience its first heat cycle. They will undergo a heat cycle every 26 to 34 weeks, and it may last for up to 21 days. 

Graphic image of a black and white Boston Terrier that explains that Boston Terriers goes into a heat cycle every 26-34 weeks

While heating naturally comes in Boston Terriers, it’s essential that you understand the cycle, what happens when your pet is in heat, and what I can do to help them. 

Boston Terrier Heat Phases

A Boston Terrier will undergo the heat cycle twice a month. From there, the cycle may last for up to three weeks. While they can be sexually active throughout the year, Boston Terriers are most fertile at around 12 to 15 months, once they attain adulthood’s physical and behavioral maturity.

To better understand when Boston Terriers go into heat, I must learn about how the breed’s growth stages coincide with the heating cycle.

The reproductive cycle of Boston Terriers has 4 phases. Each stage comes with hormonal and physical changes, as well as differing signs of behavior.


The proestrus is the starting phase of the heating cycle that lasts for 7 to 10 days. It is marked by the eggs in the ovaries starting to mature and estrogen levels starting to rise. Typically, the female’s vulva lips swell up and will discharge blood to attract mates. 

Although the female Boston terrier does not allow mating at this stage and might become aggressive to get rid of the male dog, its body is ready to receive the male’s penis. If you are planning for coitus in the next stage, you may trim the hair around its genitals and vulva for easier grooming.


This is the actual mating period that happens for 5 to 10 days. It’s the most fertile period since there will be a decrease in blood flow and the vulva will be soft and enlarged. 

Your Boston Terrier becomes willing to mate at this stage and ovulation usually occurs within the first two to three days after mating. It is also at this stage that progesterone levels are beginning to rise and estrogen levels are dropping


This is the phase after the heat that lasts for 4 to 5 months. It’s the resting stage that makes female Boston Terriers not receptive to studs (male dogs) because they are no longer fertile.

However, this stage is delicate for Boston terriers that are not meant for breeding as the long exposure to progesterone hormone may result in pyometra. 

The condition occurs when the dog’s uterus fills up with bacteria and pus and might result in death if not treated. It is advisable to spay your Boston terrier if it is not going to be mated.


The anestrus stage allows the Boston Terrier’s body to prepare for the next cycle and possible pregnancy. It lasts for around four to five months and female Boston terriers may not show interest in mating, although intact male dogs may still feel attracted to them.

Boston terrier near buildings

During this stage, the dog has no discharge, the vulva is no longer swollen since the dog uses this time to heal and repair the uterus for the next possible pregnancy.

Frequency and Duration of Heating in Boston Terriers 

Female Boston Terriers normally go into heat twice a year, about 6 months apart, each lasting for 2 to 3 weeks. 

Depending on your Boston Terrier’s health, it may take up to 18 months until the heat cycle becomes regular. In other cases, small breeds like Boston Terriers may go into heat 3 to 4 times per year. 

On the other hand, studs don’t have a sexual cycle. Instead, they would respond to female canines in heat any time of the year. Even with a 1.2% decline in sperm motility, studs can still feel attracted when females are in heat.

Signs of Heat

There are physical and emotional changes that can help notify you if your Boston Terrier is about to undergo the heating process. 

  • Overly affectionate 
  • Becomes more tired 
  • Becomes more aroused 
  • Restlessness or nervousness
  • Distracted
  • Tries to run away 
  • Swollen genital area 
  • Excessive licking of the genital area
  • Blood discharge may turn pinkish-tan
  • Increased urination 
  • Pays more attention to a potential mate 
  • Whining or crying 

What to Do When Your Boston Terrier Is in Heat

Despite heat being a natural phenomenon in dogs, your Boston Terrier would want your help to help calm down and ease any discomfort. These are some tips to care for a Boston Terrier in heat.

Keep the dog away from other dogs

An unspayed Boston Terrier can get pregnant during her first heat, so make sure to keep an eye on her. Keeping in mind that a female Boston terrier produces strong pheromones that may advertise that she is on heat when having a walk, it’s advisable to avoid places where other dogs show up, such as dog parks, doggy daycare, or dog shows.

When having a walk, keep the female Boston terrier on the lead and aim to walk late in the evening or early in the morning. If you have an unneutered Boston Terrier, it’s best to separate them during this period.

Lock the Dog up

Typically, the pheromones that female Boston terriers emit when on heat are so strong that male Bostons can detect them even when several miles away. They have the ability to track the scent all the way to your home and hang around just to try and reach your female Boston terrier.

If you don’t want your Boston terrier to get pregnant, it’s important to take precautions and ensure strict outdoor supervision even when your backyard is fenced, and no off-leash walks as their natural instincts may kick in.

When indoors, ensure that all windows and doors are securely shut. You can also provide your dog with chews or toys to play with to capture its attention and protect her from any distractions.

Boost Her Appetite

Change in appetite is a common sign that your female Boston terrier is in heat. The dog may lose appetite, particularly during the first few days of the heat cycle. However, some may be hungrier than usual, and you may find them digging in trash bins in search of something to eat.

Boston terrier lying on a pillow

Although the change in appetite doesn’t last long enough to cause visible weight loss in Boston terriers, it is important to ensure that your dog gets all the nutritional elements it requires. As a dog owner, try to entice your female Boston terrier with flavorful treats, offer them their favorite food or give them tastier cuts of meat. 

You can also add some delicious ready-made toppings or prepare a tasty unsalted chicken broth over your Boston terrier’s regular meals. Try hand-feeding the dog if it refuses to eat and give it sufficient water to ensure that it remains hydrated. 

Give it Extra Attention

During your Boston terriers heat cycle, the dog may become overly affectionate and more attached to you. It is advisable to give your dog a little more time and provide it with plenty of cuddles. Usually, cuddling helps the body release some hormones, such as serotonin and oxytocin, creating a feeling of closeness.

Dogs will experience a feeling of relaxation and happiness, helping to lower depression and improve moods. If the dog is alert and nervous, use a white noise machine to make your dog fall asleep or a diffuser with essential oils safe for Boston terriers to relax your dog.

Considering that some Boston terriers can be aggressive, try to be patient, as the aggression tends to last for a short time.

Ensure the Dog Is Comfortable

Keeping in mind that Boston terriers in heat may often feel tired and want to sleep more, it is advisable to provide a comfortable and quiet space where your pet can rest. Although Boston Terriers are good with young kids if properly socialized at a young age, it’s important to keep it away from kids during this time.

Typically, it’s because the heat cycle might be a stressful period, and additional excitement as the kids yell and run around might make your Boston terrier more stressed.

Be Patient in Frequent Potty Breaks

Your dog will have the urge to relieve herself more than usual. In addition, during the initial stage of the heat cycle, your Boston terrier will have a vaginal bloody discharge which may intensify the mess unintentionally. It’s advisable to avoid scolding your pet, and just calmly reassure her while you clean.

You can also use dog diapers for your Bostons to reduce the mess, particularly if your Boston terrier is left alone at home for an extended period of time. Although the diapers may not prevent male dogs from lurking around, they can prevent penetration in case a male dog makes its way near your dog.

Keep Your Pet Active

During the estrus phase, dogs only think of getting a mate. To distract your Boston terrier and make it focus on a different thing, you can consider getting it new interesting toys. 

Give your Boston two different toys daily and replace them after three days, as this will help keep the dog active and engaged without thinking too much about mating. 

Engage the Dog in Exercises

Considering that Boston terriers in heat might experience boredom and depression, offering less strenuous exercises to your dog, such as a non-strenuous version of fetch or brief walks around your home, can help give them some mental stimulation. 

However, it’s important to take precautions to avoid potential pregnancy or unwanted breeding. Boston terriers in heat normally have a strong impulse to run away in search of a mate, so it’s advisable to walk your dog on a leash to avoid runs.

Ensure your dog’s microchip and ID tag information are up to date to help you locate the dog easily in case it runs away. If there are many free-roaming dogs around your vicinity, it’s important to cover the scent of your dog in heat by applying some menthol on the tip before leaving the house.

Black and white Boston Terrier sitting on a green grass wearing a yellow scar and collar

Continue Grooming the Dog

Generally, frequent baths are not good for Boston terrier’s fur and skin, and it’s recommended to bathe them after every two to six weeks. However, the heat period is a bit different due to changes that might affect overall hygiene.

Vaginal bloody discharge is one of the most common changes in a Boston terrier in heat. Although Boston terriers might try to keep their private parts clean by licking themselves, it is advisable to still offer extra baths to your Boston Terrier or use wet wipes to remove blood on the skin. 

Neutering and Spaying in Boston Terriers

Neutering, also known as castration, is a surgical procedure of removing your male Boston terrier’s testicles so that he is unable to reproduce. On the other hand, spaying, technically known as an ovariohysterectomy, is the process where the uterus, ovaries, and fallopian tubes of a female Boston terrier are removed.

You can neuter your male Boston terriers when they are one year old. The ideal age for spaying Boston terriers is between one to two and a half years of age to avoid health issues. 

It is also advisable to wait until the dog undergoes its first heat cycle. Some of the health effects of neutering and spaying your Boston terrier include: 

  • Spaying female Boston terriers reduce the risk of perianal fistulas, pyometra, cervical, uterine, ovarian tumors, and mammary tumors.
  • Neutering reduces the risk of testicular cancer, non-cancerous prostate disorders, and perianal fistulas.
  • Spaying a female Boston terrier before two and a half years of age increases the risk of osteosarcoma and doubles the risk of urinary tract tumors. It’s, therefore, advisable to consult your vet or breeder on the best time to neuter or spay your Boston. 
  • Neutering increases the risk of bone cancer, hypothyroidism, orthopedic disorders, cardiac hemangiosarcoma, and urinary tract infections.

Frequently Asked Questions

How to Stop Unwanted Pregnancies in Boston Terriers?

While veterinary abortion is an effective way to terminate the pregnancy, this is a risky procedure that can harm your Boston Terrier. The best way to avoid unwanted pregnancies is to spay female dogs and neuter male ones.

What’s the Breeding Age for Boston Terriers? 

Although Boston Terriers can mate once it starts the heating cycle, it would be best to wait for your pet to become physically mature at around 2 years old. In this way, there’s a better chance that the pregnancy will push through and your pet is in a healthier state. 

Boston Terrier Heat Cycles 101 - What You Need To Know


Boston Terriers may first experience heating at around 6 to 8 months old. From there, they would go into the heating cycle every 26 to 34 weeks. Watch for signs, monitor the duration, and make sure to provide the best care for your Boston Terrier.

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