Should You Spay Your Dog? The Pros and Cons.


You should spay your dog if you are confident that it is the right decision for her, and for your family. Spaying dogs is a topic that is shockingly contentious. Nowadays, the answer is rarely a straightforward yes or no.

For many years now,  veterinary surgeons have been recommending the routine spaying of all female dogs which are not going to be bred from. Neutering often takes place at a very early age, this seems to be widely accepted as the ‘right thing’ to do, and a useful form of population control.

Veterinarians tell us that spaying your dog will protect her against life threatening disease such as mammary cancer and pyometra. Some breeders counter that the benefits of spaying have been overstated. That this is a major procedure which is risky in itself and has serious unwanted side effects.

And there are merits to both arguments.

How common is mammary cancer in dogs?

On the face of it, the incidence of mammary tumors in unspayed female dogs appears to be worryingly high. Most sources state that a quarter of all unspayed female dogs will develop mammary tumors at some point. And about half of these tumors will be malignant. Sounds worrying doesn’t it?

What does spaying achieve?

Most sources state that the risk of mammary tumors in dogs spayed before their first season is negligible, and before her second season is around 8%, rising to 25% afterwards. In other words, if you wait until after the second  season, it is too late  to reduce the risk of mammary tumors.

These two sets of figures have been widely quoted for several years When looking at statistics they are of course often not as straightforward as they seem.

A review was published in 2012 looked thirteen separate reports on the association between neutering and mammary tumors. Nine of these reports were considered to have a high risk of bias. The remaining four studies had a moderate risk of bias.

One of the studies found an association between neutering and reduced risk of tumors. Two of the studies found no association. A further study presented no numbers. Due to the high risk of bias and the weak evidence, the systematic review concluded that the evidence for the efficacy of spaying as a protection against mammary tumors is weak.

What does this mean?

Sadly, it means that we really don’t have enough evidence to draw any conclusions on whether or not neutering helps reduce the risk of mammary tumors, and that more and better research is needed into this subject.

It is probably fair to say however, that most vets still support neutering and see it as a helpful way to reduce the risk of mammary tumors.

Other factors involved in mammary tumors

Differences in susceptibility to cancer may vary from breed to breed, between large dogs and small, between purebred and crossbred dogs and depending on environmental influences.

One study showed that unspayed female dogs who were thin as puppies had half the risk of developing mammary tumors as those that were not thin as puppies.

Some studies are carried out on a very small number of subjects, and some come to different conclusions than others.

Just as in humans, there appears to be a genetic element in the risk factors for canine mammary tumors. If siblings of your dog or her mother, have developed mammary tumors, then your female dog is at greater risk. This genetic component is presumably why pedigree dogs are also at increased risk.

Spaying Your Dog vs Pyometra

Pyometra is a very nasty infection of the uterus or womb.   It tends to occur in older female dogs a few weeks after the end of their season. When a female dog contracts pyometra, pus builds up inside the uterus which is stretchy, and becomes more and more swollen.

The female dog may even start to look pregnant.    It’s a bit like appendicitis but in a much larger organ. If the cervix, or entrance to the uterus, remains closed,  the disease may go undetected until the infection is so advanced that the dog cannot be saved.

If you are lucky,  your dog will have a discharge and the infection will be detected before it kills her.

Pyometra is undoubtedly painful,  but dogs, like many other animals, tend to hide pain (a survival mechanism) until it becomes unbearable.

It is a fact that Pyometra kills dogs.

Pyometra is an often silent and deadly killer, but most importantly its prevalence is widely understated. People worry a great deal about mammary cancer,  but unless she is a cancer prone breed, your female dog is probably far more at risk from pyometra.

One American study  showed that the risk of pyometra in a female dog over nine years old is a shocking 66%. A study in Sweden where only 7% of dogs are routinely neutered, showed that around 25% of female dogs would have experienced this disease before the age of ten. That figure ranged from 10% to 54% depending on the breed.

With every season she goes through and for every year that goes by,  the risk to your female dog increases. The standard treatment for pyometra is an emergency spay.  This is a far more risky, and much more expensive, operation than a standard  routine spay for your dog

The Benefits of Spaying your Dog?

The evidence to suggest that spaying your female dog early in life (before her second season) will protect her from mammary tumors is weak. More research is needed to confirm this.

Spaying later in life may be less likely to confer protection, than spaying at a very early age. Spaying at any age offers your dog almost complete protection against pyometra afterwards.

Detecting this horrid disease is often very difficult and the evidence suggests that as your female dog becomes elderly she is more likely to get it than not.

Spaying of course has the added advantage for the owner who does not wish to breed, of removing the heat cycle so that the female dog can be worked/taken out in public, all year round. But what is clear from recent studies, is that there are risks as well as benefits, to spaying your female dog.

The Disadvantages of Spaying your Dog?

Before you whisk your female dog down to the vet, we need to look now at the other side of the coin. Some research has shown that spaying may in some respects, be disadvantageous to your dogs health.

Studies have shown increased risk in joint problems, urinary incontinence and in several other types of cancer in female dogs that have been spayed, compared with female dogs that have been left intact. This is obviously something we need to consider before booking our female dogs in for a spay.

Spaying your Dog risks Urinary Incontinence.

A recent systematic review has looked at the increased risk of incontinence in the female dog after spaying.  Seven studies were identified of which four were at high risk of bias.

The review concluded that there was some weak evidence to suggest that spaying may be associated with increased risk of urinary incontinence.

Especially if carried out before three months old.

Urinary incontinence in spayed female dogs may be treatable with hormone replacement.

Much more worrying is the recent research into the association between neutering and the risk of certain cancers.

Cancer Risks of Spaying your Dog.

Some studies have shown that spayed female dogs, whilst less at risk from mammary cancer, are more at risk from some other cancers.

A study on golden retrievers in 2013 showed an increase in risk of two different types of tumor in female dogs that were spayed later in life, compared with those that were left intact.

It also showed a significant increase in CCL (cruciate ligament) tears in female dogs spayed early in life.

A study on Hungarian Vizslas (over two thousand of them) showed a significant increased risk of several types on cancer in female dogs that had been spayed, compared with those that had not.

These risks from other types of cancer, may balance out the advantages of a reduction in mammary cancer through spaying. If indeed there is one.

Joint problems in Spayed Dogs

Sex hormones are involved in growth, and in slowing the growth of an animal as it reaches puberty.  Dogs that are neutered before sexual maturity grow longer leg bones.

This alters the angle of the joint and may be the reason that studies have shown an increase in serious joint problems in female dogs that have been spayed.

This is important, not only for working dogs, but for pet dogs too.  CCL tears involve expensive surgery and  long periods of inactivity and crate rest.

Spayed Dogs Coat Condition and Temperament

Last but not least, your spayed female dog is also likely to experience permanent changes in coat condition. This is unacceptable to those who are showing their dogs.

There is also a perception that the female dog who is spayed very young may develop mentally in a different way from the entire female dog

Perhaps altering her drive and potential in competitive fieldwork, though I could not find any concrete evidence for this.

Nor is such evidence is likely to be forthcoming as gundogs do not complete their training before their second heat.

Should I Spay My Dog?

Because the competitive dog does not reach or show her full potential until after the optimum time for spaying.

Selecting which female dogs to spay and which female dogs to breed from is problematical for owners of working or competition Labradors.

Removing ovaries and uterus as a means of enhancing and prolonging a working dog’s life is unlikely, therefore, to become popular amongst serious field triallers and dog breeders.

Especially with the increased risk in joint problems being a factor.

For pet dog owners,  the situation is also still far from clear.

The possibility of reduced risk of mammary cancers in intact female dogs may be outweighed by the risks of other cancers in spayed female dogs.

The Labrador Handbook by Pippa Mattinson(paid link)

The situation with regard to pyometra is an important consideration.  If you leave your female dog unspayed throughout her life,  she may well develop pyometra.

For that reason alone, some owners will chose to spay their female dog at some point.

We Need More Evidence – The Discussion Continues!

The evidence for the benefits of spaying for the pet dog is incomplete. Whether you view such intervention as a ‘mutilation’ or as a ‘life-saver’ is very personal matter and a choice that each dog owner has to make for themselves.

We have made several changes to this article since it was originally published. Do please let us know if you think this article needs updating again with new research.

If you have any concerns about your dog’s health, you should contact your veterinary surgeon.

Further reading

The Labrador Site Founder

Pippa Mattinson is the best selling author of The Happy Puppy Handbook, the Labrador Handbook, Choosing The Perfect Puppy, and Total Recall.

She is also the founder of the Gundog Trust and the Dogsnet Online Training Program 

Pippa's online training courses were launched in 2019 and you can find the latest course dates on the Dogsnet website


  1. I would definitely NOT have my girl fixed; ever. My beautiful girl is just shy of 9yo., she has had incontinence for 3 years. The Vet says it is clearly from being fixed before her first heat. 2 years ago she tore her ACL, and the Vet said this was suspected to be related to early spay and advised for additional joint issues. Recently, she was diagnosed with arthritis and joint issues in her spine. This Vet-Tech said she is old, offered her no pain med., and said I have decisions about the rest of her life. Nope, I would not have had her fixed until she was older, and I certainly hope anyone with a female Lab. reads this. I am heartbroken over the consequences of doing this to her. And the Vet; they said she is just too old for surgery. Wow.

  2. I’m now in the situation to make a decision if, and when best to spay my female, 5 months old pup, and found this information very helpful. It also made me look for some more recent information and I found this abstract from 2017 (; title “Neutering of female dogs – old and new insights into Pros and Cons”) that takes into account the points indicated here, but where it also says regarding the risk of other forms of cancer and HD in spayed dogs the following:

    “Recently, several studies have been published suggesting a significantly higher risk of different forms of neoplasia and musculoskeletal disorders in neutered dogs. However, factors that may bias these findings, including nutritional condition, age and/or housing, were not addressed in most studies.”

    And it concludes as follows:

    “The optimal time may be between the first and the second heat. It can be suggested, that at this time, a certain reduction of the risk of mammary neoplasia can be achieved with only a moderate potential for undesired side effects.”

    I might just do that.

  3. We have a 6month old labrador from working dog stock who has been diagnosed with the canine herpes virus. She has slight incontinence when she sleeps but otherwise knows to go outside. We want to be able to put her in home boarding occasionally but the local council licensing means that no-one can take her until she is spayed.
    Would you recommend waiting until her first season before getting her spayed?

  4. One other option not mentioned here is a tubal ligation. this proceedure can be done while puppy is young. When done with laproscopics, it is not invasive at all. You can still decide to have the orvaries removed at a later date.

  5. We were encouraged to have our Labrador puppy spayed before she had her first ‘heat’ as we were told it reduced the risk of mammary tumours. The spaying didn’t seem to alter her character in any way and she did not grow very big, she never had any joint problems and her coat remained a lovely silky black. However, when she was 9 1/2 she was diagnosed with a huge cancer mass that was inoperable because it was just behind her heart. She did undergo chemotherapy which meant she lived for another two to three years but when she was 12 she began to have breathing difficulties and sadly died one night.

  6. In common with Yvonne Mustapha (April 16, 2016), I am interested in a competently performed ovary sparing spay for my Labrador, now two and a half years old. It seems to me that the main risk of not spaying is Pyometra. If just the uterus (+ stem?) is carefully and fully removed this risk will be removed (a possible increased risk of mammary cancer will remain). The risks of a full spay (joint problems and cancers other than mammary and urinary incontinence) are, as I understand it, associated with the consequent absence in hormones produced by the ovaries. Thus ovary sparing spay seems optimum, if done carefully so that no uterine tissue remains. When I tried to find a vet to do this I could not. Why do no UK vets offer this or develop the expertise to offer it please?

    • i would say Kate,vets might as well do a full hysterectomy because once the blood supply to the ovary is cut off,they shrivel up and die anyway so no hormones whatever you do,no easy answers to this one

  7. I have recently looked up part spaying where the whole of the uterus ( + the stem ) is removed but the Ovaries are left intact. This seems to lower the risk of Osteo-sarcoma ( bone cancer ) which also occurs more in certain breeds of dogs.
    This makes sense as in the human female if the whole of the womb is removed they need hormone replacement treatment after, but if possible only the uterus is removed and the ovaries are kept .
    Has anyone looked into this and if there is a Vet that does this form of Spay in Buckinghamshire

  8. We had our fox red lab spayed when she was 11 months old, a couple of months after her first season. We wanted wait until she had matured and were advised this was best. My mum had her black lab spayed before her first season.
    Our dog seemed to calm down much quicker than my mums and although that might be down to genetics I do believe that spaying before her first season contributed to her very boisterous behaviour
    However we noticed around 3 years afterward ours had been spayed she had urinary incontinence, she is on propalin and will be for the rest of her life we were told this was a risk of spaying after the first season.
    We now have a chocolate puppy, and have decided to wait until after her first season (which we wish would hurry up as she is now 10 months old!) but we think we may go for the laprascopic spay, as this is now an option, fingers crossed she will calm down a bit when she matures!! We feel the need to spay ad we don’t want unwanted puppies as we’re just not in a position for this and not being able to walk her for 3-4 weeks is going to drive both us and her insane so we don’t want to stress her out more than once!

  9. We had our female lab spayed at 6 months before her first heat and I regret that now. While she came through the surgery easier than my previous lab that was spayed at 1-1/2, we are now dealing with occasional incontinence in our 2 year old lab. If I knew then what I know now, I would have waited. We have had several females of different breeds over the years spayed at different ages with no mammary cancer or incontinence. My next female will be spayed after 1 or 2 seasons.

  10. My black lab who is 7 soon is currently in season. Very irratable, is frustrated her walking off the lead has had to stop and is acting slightly different? I’m deciding if to get her spayed but not sure as she is older. Can anybody help me please xx

    • I have an 8 year old chocolate lab who we decided to have spayed 3 months ago. We made this decision as she has twice in the past had Pyometra the last time being December 2014 the first time we almost lost her but we foolishly believed she wouldn’t get it again which of course she did.
      Getting her spayed was just the best decision,Milly is a different dog she is happier and has lots more energy and life, when the vet operated cysts were found all along her uterus which we were unaware of.

  11. I had our Lab spayed after her 1st heat. I was worried about pyometra because our last dog had an open pyometra and luckily I was able to bring her to the vet quickly.

    I also do not want any unexpected litters. I’ve read studies and articles about the disadvantage of spaying. At 18 months, my Lab was diagnosed w/ osteoarthritis. I felt so guilty I thought it was a direct result of her spaying, though my Vet assured us that it MAY NOT be caused by spaying. I don’t know anymore. I wish there’s more information out there and more studies.

    Now my Lab is taking Cetyl-M, we’ll have periodic xrays to monitor her athritis and if it progresses, we’re looking into stem cell as an option.

  12. I have heard that from friends’ experiences that spaying will cause incontinence in female labs and they have to be on pills their whole life to prevent bed wetting. Is that true?

  13. My year old lab has just come into season. I am thinking of having her spayed but my partner fears that she will put on weight if this is done. Is he right?

  14. Are there behavior advantages to spaying? My 6 month old lab seems on edge & is mounting everything. Will spaying ease her?

  15. Thanks that’s really helpful! I’ve read both articles and am pretty sure I’ll go ahead-the only question being exactly when. Slightly worried about the bone density/hip dysplasia/bone cancer aspect of spaying, my dog being a (rather tall and thin) Labrador, although she has had her hips X-rayed and apparently they’re pretty spot on. (not scored yet). I didn’t know that was an issue..Thanks again. It’s a tricky one!