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Strange Behavior After Spay: Hormone Balancing?

Veterinary reviewed by Nicole Wanner, DVM.

Strange behavior after your dog is spayed is not uncommon which is no wonder, considering the scope and implications of this procedure.

But why exactly do odd behaviors surface and how can you deal with them and know when something’s going seriously wrong?

Luckily, I do have a couple of tips that might help with getting to the bottom of your female dog’s behavior.

Many people just attribute out-of-character behavior to hormones and while that can certainly be true, it’s not always the case.

Whether you are considering having your dog spayed or are monitoring them post-surgery, there are a number of factors to consider and behaviors to watch for.

Your dog will act differently while they recover from surgery, but these changes are usually temporary.

Spaying is unlikely to fix serious behavior issues like aggression, resource guarding, or separation anxiety.

Find a veterinarian you trust and ask them how spaying may affect your dog’s long-term behavior.

You can also go over the timing of the procedure since the best time to spay varies by breed.

If your dog is a large breed, it may help to wait until bone growth is finished.

Yes, the pros include reduced risks for various cancers and pyometra but the risk of the procedure itself as well as the possible behavioral changes need to be researched and assessed for every individual case.

Strange Dog Behavior After Being Spayed

Strange behavior after spaying is common in the first week of recovery up to a couple of weeks. Behavior changes are mostly related to pain and recovery but permanent changes are possible.

While your dog’s body recovers from the surgery and balances hormones, your dog might simply be bored due to the leash restriction or cone.

Strange behavior after a spay might also be explained due to pain or medication.

Complications such as an infection need to be examined by your vet.

Boston Terrier is brought to the vet.
Photo by Rido on Shutterstock

Strange behaviors after spaying include:

  • Whining
  • Sensitive to touch
  • Excessive urination
  • Irritability with strangers or family
  • Resource aggression or nesting

Now, many of these behaviors are reported before spaying.

Sometimes, these weird behaviors are even the reason spaying is considered in the first place.

But spaying mainly affects behaviors associated with your dog’s heat cycle, like flagging, wandering, and restlessness.

To be clear, getting your dog spayed neither means that these behaviors will stop nor does it mean your dog will display these negative behaviors after being spayed.

Even if your dog is acting weird after being spayed, it’s not necessarily a long-term change.

Whining can occur when the dog is bored, sensitivity or urination is possible due to the surgery itself, as is irritability while the hormones are still balancing.

Is it possible that your dog’s personality changes after being spayed?

White Bullterrier leans with the front paws on a table.
Photo by sukiyaki on Shutterstock

Yes, but rarely.

If you speak with your veterinarian, they will review positive changes such as heat-related behavior improvements, reduced cancer risk, and no heat cycle.

Some dogs are heavy bleeders or experience pseudopregnancies with milder physical symptoms or perhaps serious behavioral changes.

Your vet should also go over potential risks and downsides, which are important to consider for your dog.

Even though spays are one of the most common procedures that vets perform, there is a small chance something could go wrong during surgery.

There is also a small risk increase for certain cancers in spayed dogs, but it depends strongly on the breed. On the flip side, spaying reduces the risk of mammary (breast) cancer in female dogs dramatically.

There is also a greater risk of obesity because reproductive hormones affect metabolism.

But these changes can be managed with an appropriate diet.

Unfortunately, dogs don’t go through menopause. An intact female will go through heat cycles her whole life.

Extreme behavior or personality changes after spaying are very rare.

Talk to your vet if you observe something like this, as there could be a complication from surgery or other health problem to blame.

Many of these reported issues do surely disappear once your dog recovers after being spayed, feels no pain anymore, and gets exercised again.

Why a Dog’s Weird Behavior After Spaying Might Not Go Away

Recovery and hormonal balancing are not the only reasons why dogs often behave weirdly after being spayed. Increased fearfulness and sensitivity can be related to spaying.

Research about how spaying affects a dog’s personality is still ongoing.

So far, it looks like long-term changes in behavior after spaying are uncommon, mild, and depend on what age the dog is spayed at.

One study using 15,000 owner surveys found that dogs spayed or neutered between 7-12 months of age were slightly more likely to be aggressive toward strangers.

Dogs in the study who were spayed at other ages did not show more aggression toward strangers.

Interestingly enough, one news outlet cites Europe as not being so keen on spaying and while that’s true, I’ve definitely heard people state that spaying will solve their dog’s behavioral issues.

Spaying and neutering only reliably affect issues associated with hormonally-controlled mating behavior, like roaming and seeking out other dogs.

It is a misconception that males will calm down considerably after neutering without any training.

The study linked below shows that rates of aggressive behavior in intact and neutered male dogs are about the same.

Similarly, dogs that are spayed or neutered are not any easier or harder to train than before.

Another study suggests that behavior issues in “doggy adolescence” relate to how bonded a dog feels to their owner and family.

Bad behaviors can just be a temporary change and your dog might get better as they get a little older.

This is under the assumption that you consistently work on your dog’s training.

Most aggressive behaviors in dogs are a last resort caused by fear.

Understanding what you want and knowing they can go to you for help improves your dog’s confidence.

How Long For Hormones To Balance After Spaying

It takes around 2-4 weeks for your dog’s hormones to balance after spaying.

Your dog’s behavior may not be weird due to the hormones but instead because of the medication, surgery pain, or lack of exercise afterward.

Behaviors such as whining, sensitivity, and irritability may settle back down after the dog’s hormones have balanced.

As mentioned, another possibility is that your dog’s behavior has changed permanently but that chance is relatively slim.

Dog owners tend to view spaying and neutering as routine procedures.

While they are the most common surgeries performed at veterinary clinics, even a routine procedure is still a major event for your dog.

The pain, anesthesia medication, and hormone changes might make your dog feel off for a couple of days or even weeks.

Long-term changes can include increased fearfulness and sensitivity, according to two large-scale studies that indicate that more research might be necessary.

If your dog is still acting odd a few weeks after her spay surgery, contact your veterinarian.

Do Dogs Still Have Hormonal Changes After Being Spayed?

Yes, dogs still have hormonal changes for up to 2 to 4 weeks after being spayed. However, scientists don’t perfectly understand what happens to your dog’s hormones right after being spayed.

It depends on where she was in her heat cycle at the time.

Still, dogs can potentially have hormonal behavior changes that last weeks after the spay surgery.

As mentioned above, there are various weird behaviors after being spayed that can be attributed to the usual recovery and hormones but not necessarily all of them.

The majority of behavior changes after the spay are temporary. Your dog’s body is recovering from surgery and adapting to the lack of hormones from the ovaries.

Some may express these changes more (i.e. temporary irritability or sensitivity) while others never change their happy-go-lucky personality, but it’s never a sure thing upfront.

There is an alternative to the usual spay surgery where only the uterus is removed (hysterectomy). This prevents pregnancy while keeping your dog’s female hormones.

Talk to your veterinarian if you’re interested in alternative spay procedures.

Does a Female Dog’s Personality Change After Spaying?

A female dog’s personality usually doesn’t change after spaying but there is potential for some heat-related behaviors to subside while very few dogs become more aggressive, fearful, or sensitive.

Many owners do report slight positive behavior change that doesn’t exactly qualify to be called “personality change”.

Major personality changes like increased aggression after spaying are rare. Talk to your vet right away if you notice it, as something else could be wrong.

While these are important findings to evaluate whether or not a spay is necessary (especially if it’s just done to eliminate behavior) it might just be a risk many have to take for medically necessary spays.

Summary of Strange Behavior After Spaying & Hormone Balancing

Spaying does have upsides but also potential downsides which include, but are not limited to, weird behavior changes; both temporary and in rare cases long-term as proven by several studies.

Most changes are not long-term and can often be attributed to pain, medication, exercise, or hormone balancing, but a small number of dogs will change permanently.

The best age to spay your dog depends on a lot of factors, like their breed. It’s usually advised to wait until bone growth has finished.

Every spay case needs to be evaluated on an individual basis.

Age, health, and the reason for spaying need to be considered when weighing the pros vs the cons.

Behavioral issues or concerns about accidental breedings might be more easily addressed without spaying, but every case is unique.

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Disclaimer: This blog post does not substitute veterinary attention and does not intend to do so. I am not a veterinarian or pet nutritionist. If your dog shows any sign of illness, call your vet.

About Danielle

Equipped with 5+ years of expertise as a Rottweiler owner, I partner with licensed veterinarians and trainers to share research-backed and actionable advice for you and your furry friend.


Monday 7th of August 2023

My 18mth old toy poodle was spayed last week and has been excessively ‘nesting?’ Srappleing her bed about. Is this behaviour hormonal & will it be temporary?


Monday 7th of August 2023

Hi Valerie, since she was spayed just a week ago, it could be just a temporary behavior. I'd call the vet just to get their opinion and confirm what you should look out for to know when you should make an appointment. In the meantime, I'd just monitor and let the vet know about any changes.


Friday 16th of September 2022

A very interesting read. My bitch was spayed in July aged 20 months old and following her 2nd season. She has suffered behavioural changes ever since which seem to be getting worse. A couple of weeks after spaying she saw a hot air balloon and was horrified, running back home to safety. She was very scared every morning ever since and is now even scared when she sees the moon in the morning... The afternoon walks however are no issue even though we walk to the same places . This all makes perfect sense now

Denise Peiffer

Monday 29th of August 2022

My puppy is 10 months and was spayed 6 days ago. She has been carrying around a rubber ball everywhere. She has also been taking it and hiding with it in the closet. She whines a little too. Also we have another dog 10 years old and she growled at her by her food bowl and has never done that before :(


Monday 29th of August 2022

Hi Denise, as mentioned in the article it might just be that the hormones are still balancing and/or your pup might still be in pain, hence the irritability. Protecting resources such as toys or food is part of that, but it'd also make sense to consider her heat cycle (if she was in heat yet) and whether pseudopregnancy might play a role.

Generally, research has shown that spaying a pup before bone growth has changed often leads to issues. Make sure no incidents happen between your pup and older dog and ask your vet about the recovery and what they think about the behavior.

Cheers, Dnaielle