Oh wow. There’s a lot of info out there on this one. And even more opinions…

Do you spay at 6 months?
A year?
8 weeks?
2 years?
Never??

So many choices. And such an important decision. I mean, this is surgery for your fur baby for heaven’s sake!

In recent years, some studies have suggested that early ovariohysterectomy (the $2.50 word for spay) may be implicated in increased risk of bone cancer, spay incontinence, obesity, and other health problems.

Oh, okay. So the answer is to wait a good long while to spay. Or maybe not spay at all…

Wrong, and wrong!

See, the problem we have with a lot of our veterinary studies is that we just don’t get a lot of subjects. I mean, 25 dogs is a pretty decent-sized study. Compare this with human research projects that have hundreds or thousands of test subjects. And we don’t often get to do true randomized, controlled, experimental studies. A lot of the time we’re relegated to retrospective or case studies, which means the researchers are going back through reports and extrapolating data that way. Ideally, we would like to form a hypothesis and perform controlled experiments to prove or disprove our theory. And even more ideally, we would like our “n,” or number of test subjects, to be large enough to be statistically significant.

Unfortunately, even though we are now in the year 2020, we still don’t have undisputed, evidence-based reasons to spay all dogs at a certain age. So what do I tell my clients when it comes time to have this discussion?

  1. If you are not planning on breeding your dog, you 100% need to spay her. The risks of reproductive cancers and serious infections are just too high not to do it.
  2. For most dogs I recommend spaying before they experience their first heat, which usually happens around 6 months of age. Dogs spayed this early have a minimal risk of reproductive cancers.
  3. The incidence of mammary cancer doubles with just one heat cycle, and if you wait until after your dog is 2 years of age, you’re looking at a 7-fold increase in cancer risk.

This is one of those cases where science can give us guidelines, but no hard and fast rules. Yet. If you have questions about when to spay your dog, ask your vet! She can help tailor a plan to your dog’s age, breed, and lifestyle.