If you have a female dog, the question of whether and when to spay is one you’ll probably face at some point. For many years, vets have strongly recommended routine spaying. There are genuine health benefits that make it worth considering. But when it comes to dog behaviour after spaying, the picture is more complicated than most owners are told. And perhaps surprisingly, the research specifically looking at how spaying affects female dog behaviour is thinner than you might expect.
This article focuses specifically on female dogs. If you have a male dog, we’ve written a companion article on castration and dog behaviour. It covers the male-specific evidence, including chemical castration as a reversible alternative.
The Health Trade-Offs
Spaying does offer some important health protections for female dogs. It significantly reduces the risk of mammary tumours (the equivalent of breast cancer). It also eliminates the risk of pyometra, a life-threatening womb infection that affects roughly one in four unspayed bitches. These are real benefits that your vet will rightly factor into their advice.
However, like any surgical procedure, spaying also carries some risks. These include urinary incontinence and, in certain breeds, associations with some orthopaedic problems and cancers. How these balance out varies considerably from breed to breed. Your vet can weigh them against the benefits for your individual dog.
The point isn’t to alarm you, but to make clear that spaying isn’t a risk-free procedure. It’s a trade-off that your vet can help you weigh for your individual dog. For many dogs, spaying is absolutely the right choice. The aim of this article is to help you make an informed, individual decision, not to discourage it.
Dog Behaviour After Spaying: What Does the Research Say?
This is where things get interesting. In 2023, a scoping review in the Veterinary Record charted the evidence on how spay timing affects female dog behaviour. The researchers screened the available literature and found that only a small number of studies met their criteria for inclusion. Their conclusion was striking: there is a lack of evidence to document the impact of neutering bitches before or after puberty on behaviour.
That doesn’t mean spaying has no behavioural effects. It means we know much less than many people assume, and the studies that do exist often have conflicting findings. Many didn’t separate male and female results or used inconsistent definitions of timing. Some didn’t account for behaviour problems dogs already had before their spay.
What we can say, drawing on the best available evidence, is the following.
Fear, Anxiety and Dog Behaviour After Spaying
Some studies have reported higher levels of fearfulness in spayed females than in entire females. For example, owners of spayed Labrador Retrievers reported more frequent or intense reactions to loud noises, unfamiliar objects, and unknown dogs approaching (Balogh et al., 2018). It’s worth remembering that these are group-level associations from owner-report studies, not a certainty for any individual dog.
A large-scale study looking at nearly 9,000 female dogs found that longer lifetime exposure to gonadal hormones was associated with reduced fearfulness and reduced aggression. This suggests that allowing dogs more time with their natural hormones before spaying may have a protective effect. However, the differences were relatively small, in the range of 5–7%, so this shouldn’t be overstated.
We cover the broader evidence on fear and anxiety in neutered dogs of both sexes in more detail in our castration and behaviour article. That includes the role of increased luteinising hormone (LH) after neutering, and much of it applies equally to females. As we explain there, the raised-LH link to fear and anxiety is a proposed mechanism still under investigation, rather than settled fact.
Aggression and Dog Behaviour After Spaying
The relationship between spaying and aggression in female dogs is complicated. Some research has found that spayed females are more likely to show owner-directed aggression (an older term for this was “dominance aggression”). Other studies have found no clear effect. One prospective study (O’Farrell & Peachey, 1990) found that bitches already showing signs of aggression were more likely to become more aggressive if spayed before a year of age. The evidence is mixed, though – other work has found neutered bitches among the least likely to show aggression towards people (Casey et al., 2014).
For aggression between female dogs in the same household, vets sometimes recommend spaying. But it’s important to understand the limitations. Inter-bitch aggression sometimes begins or worsens when one or both dogs come into season. However, it often continues throughout the cycle and into anoestrus (the hormonally quiet period between seasons). If the aggression persists outside of seasons, spaying is unlikely to resolve it, because hormonal fluctuations are no longer the main driver of the behaviour.
If your female dog is showing aggressive behaviour, it’s important to understand what’s motivating it before you make any decisions about spaying. Fear-based aggression, in particular, is unlikely to improve with spaying and may get worse.
Dog Behaviour After Spaying: What It Can Help With
Spaying does reliably eliminate behaviours that are directly tied to the reproductive cycle. These include the behavioural changes associated with being in season (restlessness, increased vocalisation, attracting male dogs). They also include the sometimes challenging behaviours linked to pseudopregnancy, such as nest-building, guarding objects or toys, changes in appetite, and occasionally defensive aggression.
If your dog experiences difficult pseudopregnancies or if managing seasons is causing significant welfare concerns, these are legitimate reasons to consider spaying. Discuss this with your vet, who can also advise whether medical management has a role first.
The Surgical Experience Matters Too
Something often overlooked is that the surgical experience itself can affect your dog’s behaviour. Spaying is a more invasive procedure than castration, with a longer recovery period and more post-operative discomfort. For nervous dogs, the hospitalisation, separation from owners, unfamiliar handling, and recovery restrictions can be genuinely stressful. That stress can compound existing anxieties or create new ones.
This is especially important for dogs going through their adolescent period, when they’re developmentally more vulnerable to the effects of stressful experiences. Post-operative complications, although uncommon, can further impact a dog’s emotional state – particularly if they lead to additional vet visits or prolonged discomfort.
If spaying is going ahead, there’s a lot you can do to reduce the stress of the experience. We’ve included practical guidance on preparing your dog before, during, and after surgery in our companion article on castration and behaviour. All of that advice applies equally to female dogs having a spay.
Ovary-Sparing Spay: An Emerging Alternative
One option that’s gaining attention is the ovary-sparing spay (also called a hysterectomy). The vet removes the uterus but leaves the ovaries in place. This prevents pregnancy and removes the source of pyometra while allowing the dog to retain her natural hormones.
A 2023 US study compared health and behaviour outcomes for over 6,000 dogs with different reproductive statuses. It linked longer exposure to gonadal hormones with lower odds of health problems and problem behaviours, whatever the sterilisation method. Female dogs who had undergone ovary-sparing spay retained their hormonal exposure while still being sterilised.
It’s worth noting that ovary-sparing spay is still relatively uncommon in the UK, and it does come with trade-offs. Dogs will continue to have seasons (with the associated behavioural changes and attractiveness to males). They also won’t receive the mammary tumour protection that comes with removing the ovaries. Your vet can help you weigh up whether this option might be appropriate for your dog.
Chemical Options for Female Dogs
You may have heard of deslorelin (Suprelorin) implants as a reversible alternative to castration in male dogs. Deslorelin can also be used in female dogs, but the picture is more complicated. In bitches, the implant can initially stimulate a season before it suppresses reproductive function. The timing and effects can be less predictable than in males.
For this reason, deslorelin use in female dogs requires careful veterinary guidance and isn’t as straightforward a “trial run” as it can be in males. Your vet or Veterinary Behaviourist can explain whether hormonal suppression might suit your dog, and what to expect.
Making the Right Decision for Your Dog
The decision about whether and when to spay your dog is one for you and your veterinary team. Your vet – or, where behaviour is a concern, a Veterinary Behaviourist – is best placed to weigh up the health and behavioural risks and benefits for your individual dog. They will take into account her breed, size, age, temperament, and any existing behaviour concerns.
If your dog is showing unwanted behaviours, the most helpful first step is often a behavioural assessment before any spay. A Clinical Animal Behaviourist or Veterinary Behaviourist can help identify what’s driving the behaviour. Is it hormonal, learned, rooted in fear or anxiety, or related to an underlying health issue? This assessment helps your vet decide whether spaying is right for your dog, or could make things worse.
Current expert guidance supports an individualised approach. There is growing caution about spaying before puberty, particularly in larger breeds. Physical health drives this more than behaviour, where the evidence on timing remains limited. The evidence base is still developing – particularly for female dogs. The most important thing is to make the decision carefully and collaboratively, with your dog’s overall wellbeing at the centre.
How We Can Help
If you’re concerned about your dog’s behaviour – whether you’re weighing up the spaying decision or you’ve already had it done and things haven’t gone as expected – we can help. At Second Nature Behaviour, we work on veterinary referral. We provide a thorough behavioural assessment and a tailored plan that addresses the real causes of the problem. We’ll work alongside your vet. All our recommendations, including advice on the spaying decision, will rest on the best available evidence and your dog’s needs. Get in touch with us to arrange a consultation.
References & Further Reading
Balogh, O., Borruat, N., Meier, A., Hartnack, S. & Reichler, I.M. (2018). The influence of spaying and its timing relative to the onset of puberty on urinary and general behaviour in Labrador Retrievers. Reproduction in Domestic Animals, 53(5), 1184–1190. https://doi.org/10.1111/rda.13225
Casey, R.A., Loftus, B., Bolster, C., Richards, G.J. & Blackwell, E.J. (2014). Human directed aggression in domestic dogs (Canis familiaris): occurrence in different contexts and risk factors. Applied Animal Behaviour Science, 152, 52–63. https://doi.org/10.1016/j.applanim.2013.12.003
Moxon, R., Freeman, S.L., Payne, R., Corr, S. & England, G.C.W. (2023). Effect of neutering timing in relation to puberty on female dog behaviour – a scoping review. Veterinary Record, 193(1), e2882. https://doi.org/10.1002/vetr.2882
O’Farrell, V. & Peachey, E. (1990). Behavioural effects of ovariohysterectomy on bitches. Journal of Small Animal Practice, 31(12), 595–598. https://doi.org/10.1111/j.1748-5827.1990.tb00701.x
Starling, M., Fawcett, A., Wilson, B., Serpell, J. & McGreevy, P. (2019). Behavioural risks in female dogs with minimal lifetime exposure to gonadal hormones. PLOS ONE, 14(12), e0223709. https://doi.org/10.1371/journal.pone.0223709
Zink, C., Delgado, M.M. & Stella, J.L. (2023). Vasectomy and ovary-sparing spay in dogs: comparison of health and behavior outcomes with gonadectomized and sexually intact dogs. Journal of the American Veterinary Medical Association, 261(3), 366–374. https://doi.org/10.2460/javma.22.08.0382