14/01/2026
First, no one wants unwanted litters! 🐶 Spay and neuter has saved countless lives, but the issue is more complex than we once thought.
A massive review of 40+ years of veterinary records (over 2 million dogs) revealed something important: neutered dogs, especially spayed females, were more likely to develop hemangiosarcoma, one of the most aggressive canine cancers. Spayed females faced up to a 72% higher risk, while neutered males had a smaller but still measurable increase, mainly for spleen tumors, not heart ones. Even after researchers matched dogs by age and time period, the link stayed strong, showing this isn’t just about early spay/neuter trends but how hormonal shifts can influence other body systems. The takeaway? Each dog’s biology, breed, and hormones matter…and when it comes to lifelong health, one size doesn’t fit all.
These findings remind us that traditional spay/neuter may carry risks, and alternative sterilization techniques, like ovary-sparing spay or vasectomy, should be considered to support long-term health.
PMCID: PMC7155881