When Should You Spay or Neuter Your Dog?

For decades the standard answer was "six months for every dog." Research over the last decade, especially on large breeds, has changed that. The American Animal Hospital Association (AAHA) now recommends basing the timing on the dog's expected adult size and individual risks.

Recommended age to spay or neuter a dog

Source: AAHA. Your veterinarian will tailor the timing to your dog's breed, health and home situation.

Why large breeds are often fixed later

AAHA cites a 2013 University of California, Davis study of golden retrievers that linked early spaying and neutering with higher rates of some joint disorders (cranial cruciate ligament rupture and hip dysplasia) and some cancers (hemangiosarcoma, mast cell tumors and lymphosarcoma). Researchers say more breed-specific study is needed, but the findings are why many vets now wait until large dogs finish growing.

Why small breeds are often fixed earlier

Small dogs reach maturity sooner, and spaying before the first heat greatly reduces the risk of mammary cancer. Waiting longer in small dogs adds risk of unplanned litters and heat cycles without the same orthopedic benefits seen in large breeds.

Benefits of spaying and neutering

• Spaying greatly reduces the risk of mammary cancer and prevents pyometra (a life-threatening uterine infection) and heat cycles.
• Neutering eliminates the risk of testicular cancer and reduces roaming, marking and fighting with other males.
• Both prevent unwanted litters.

Possible downsides to discuss with your vet

AAHA notes that cancer, orthopedic disease, behavior problems, hormone disorders, obesity and urinary incontinence may be linked to sterilization and its timing. Weight gain after surgery is common but manageable by adjusting food. These risks are why AAHA stresses an individual decision, especially for large and giant breeds.

Can you spay a dog in heat?

Many vets prefer to wait until a few weeks after the heat ends, because blood vessels are enlarged during heat and the surgery carries more risk and often costs more. Ask your vet.

Is it ever too late?

No. Adult and senior dogs can be spayed or neutered safely after a health check and blood work. The benefits (for example, preventing pyometra, whose treatment Rover's 2025 data puts at about $1,300 to $2,400) still apply.

See how much it costs to neuter a dog and to spay a dog, and find veterinarians near you.

Sources

1. AAHA: Spay or neuter?
2. GoodRx: How much does it cost to spay or neuter your dog or cat? (2024)
3. Rover: How Much Is a Vet Visit for a Dog? (2025)