Pros and cons of spaying or neutering your dog or cat at an early age

When it comes to being a new pet parent, the decision to spay or neuter your pet—and when—is one of the most important that you can make. If you’ve just brought home a new puppy or kitten that hasn’t been sterilized yet, how can you know when the right time is?

Animal Humane Society recommends all pets be sterilized. To learn about what to consider when determining when to spay or neuter your pet and what the pros and cons are to sterilizing animals at different ages, we talked with Dr. Graham Brayshaw, DVM, Director of Veterinary Medicine at Animal Humane Society.

German Shepard in white medical cone.

Pet sterilization reduces animal overpopulation

Perhaps you're familiar with Bob Barker's famous sign off on The Price is Right: "Help control the pet population. Have your pets spayed or neutered."

In Minnesota, we still have many stray cats, while our stray dog population is declining. In other areas of the country, and the world, there are many stray cats and dogs. High numbers of stray animals in the community challenges capacity at animal shelters and rescues and can lead to having to euthanize animals due to space constraints.

To do our part to address pet overpopulation in our community, AHS sterilizes the animals in our care starting at 6-8 weeks old to ensure every animal is spayed or neutered prior to adoption.

“At Animal Humane Society, our focus is to care for individual animals, while also addressing larger community issues in animal welfare, like pet overpopulation,” says Dr. Graham. “That’s why we sterilize every animal before they’re made available for adoption, regardless of if they’re puppies, kittens, or full-grown adults."

A variety of factors to consider

The decision of whether to spay or neuter your pet is a personal one and may be influenced by a whole host of factors, including:

  • Your and your pet’s lifestyle: Do you love visiting the dog park or being social with other pets? Have you always wanted to welcome a litter of puppies or kittens into your home?
  • Your pet’s breed: Is your pet a purebred or a mix of breeds?
  • Environmental factors: Do you live in an area with a lot of other pets who may not be sterilized? Could your pet easily escape your house or yard?
  • Cultural or societal beliefs: Different areas of the world, and even different parts of the United States, have varying norms around spaying and neutering pets. Where you were raised or where your family lives may influence your approach.

When's the right time to spay or neuter your pet?

You've decided to spay or neuter your pet, but do you know when they should have the surgery? There are both medical and behavioral considerations that may influence your decision. 


Reasons for earlier sterilization: 

  • Every heat cycle an intact female dog goes through increases their risk of mammary cancer. Intact females are also at risk of pyometra, which is an infection of the uterus. Pyometra is life threatening and requires emergency spay surgery. 
  • Intact male dogs are more prone to developing benign prostatic hyperplasia (a non-cancerous enlargement of the prostate), cysts or infections in the prostate, and testicular cancer.
  • These conditions could mean a shorter life for your pet, and treating these conditions can be more expensive than the one-time cost for sterilization.
  • If you live in an area with other pets nearby, especially unsterilized animals, or you regularly visit a dog park, spaying or neutering your pet can protect them from unplanned breeding and decrease the risk of them escaping to roam and find a mate.
  • Putting an animal under anesthesia is never risk-free, however the risks are very small. Approximately only one in 1,000 healthy animals experience life-threatening complications from being put under anesthesia.

Reasons to delay sterilization:

  • Some retrospective studies have recently been published that show very early sterilization may delay closure of growth plates in big bones, meaning the animal gets a little bigger or longer. In some breeds, like German Shepherds and Golden Retrievers, this may lead to hip or joint issues. In other breeds, it seems to have no impact.
  • Retrospective studies have also shown some evidence in German Shepherds and Golden Retrievers that round cell tumors (hemangiosarcoma and lymphoma) may be a slightly more prevalent in cases of early sterilization.
  • Sterilization results in less testosterone and estrogen. Testosterone and estrogen are good for muscle and bone development. When testosterone and estrogen levels decrease, dogs burn fewer calories. This requires diligent control of their food intake to manage their weight properly. 
  • While sterilization and behavior impacts haven’t been studied, there is a common perception that testosterone leads to aggression. There isn’t any good scientific evidence that shows that an intact dog will have more behavior concerns. An animal’s personality is set more by how well they’re socialized in the important beginning stages of their lives.


Reasons for earlier sterilization: 

  • Like female dogs, the more heat cycles female cats go through, the more at risk they are for mammary cancer and uterine infections. Sterilization also decreases spraying behavior.
  • For male cats, the main reason to neuter them is to reduce spraying behavior. Additionally, intact male cat urine becomes increasingly smelly as they age — you’ll likely be able to smell it in your home even if they use the litter box perfectly.
  • Sterilizing cats also helps avoid unplanned litters and other behaviors associated with being in heat. Female cats reproduce quickly and can start reproducing as early as four months of age. They have multiple estrous cycles during the breeding season (April to October), which means they can have more than one litter in a year. When in heat, females will spray, vocalize loudly, and try to get outdoors to roam. Unneutered male cats will also spray and try to escape to find females in heat. 

Reasons to delay sterilization:

  • There’s no reason to delay sterilization for a female cat. Sterilizing your cat while they’re young will decrease their risk for mammary cancer and uterine infections, remove the chance of an unplanned litter, and reduce behaviors displayed while in heat.
  • A handful of retrospective studies have suggested that early sterilization of male cats may contribute to hip issues when they’re around a year old, however the incidence of this issue is very low and hasn’t yet been proven.










What age to sterilize your pet


  • Females: A dog’s first heat cycle is generally between seven and 10 months of age. To reduce the risk of mammary cancer or pyometra as much as possible, spay your dog before they’re seven months old. If you decide to breed your dog and have one litter of puppies, spaying is still recommended after they birth their first litter to reduce their risks.
  • Males: The health risks for intact males typically don’t develop until later in life, so while you can wait to neuter your male dog at an older age than a female, it’s still recommended to neuter your dog at a younger age. 


  • Females: Any time before their first heat cycle, generally before seven to 10 months of age. Scheduling their spay surgery for the same time as their last round of vaccines at four months of age is a great rule of thumb. If you decide to have a litter of kittens, spaying is still recommended after they birth their first litter to reduce their risks.
  • Males: Any time before seven to 10 months of age. Scheduling their neuter surgery for the same time as their last round of vaccines at four months of age is a great rule of thumb.

While the information above provides general guidance, Dr. Graham says, “Spay and neuter decisions are best discussed with your veterinarian. They can discuss with you the different factors and risks specific to your pet’s situation and advise you on the best approach.”

Whether you decide to sterilize your pet right away or wait until they’re a little older, ultimately getting them sterilized will help reduce the risk of health complications and avoid unplanned breeding. 

Did you know AHS Veterinary Centers offer spay/neuter services?

Animal Humane Society Vet Centers offer high-quality, low-cost vet services with two fee tiers based on income, including spay and neuter services. Request a spay/neuter appointment, or learn more about what to expect from surgery recovery.

Schedule a Spay/Neuter Appoitnment