Ovariectomy vs. Ovariohysterectomy: How the Spay Got Lost in Translation

Medical Articles

A couple of weeks ago, an alarmed novice dog owner who’d recently moved to the U.S. emailed me to ask a seemingly not-so-novice question about her year-old Viszla: “I had her spayed in Germany but now her American vet says she’s not really spayed. Does she really have to undergo this invasive procedure all over again?”

Odd question, right? I mean, since when does a spay take two tries to get right?

Turns out the question made a lot more sense once it was revealed that this German-spayed Viszla had the word “ovariectomy” included in a transcript of her medical records. And ovariectomy, so you know, is not the procedure we commonly refer to as a spay here in the U.S. Instead, “ovariohysterectomy” is the sterilization procedure preferred by most American veterinarians.

I know, I know, it’s confusing. Let me explain using of a simple etymological exercise:

“ovari” = ovaries

“hyster” = uterus

“ectomy” = removal

Hence, an “ovariectomy” procedure denotes the removal of the two ovaries that produce the eggs and secrete female hormones, thereby rendering a female sterile by leaving her bereft of any means of contributing genetic material.

This, along with the subsequent paucity of chemicals required to support any reproductive function (sex hormones) means zero negative influence on any remaining reproductive organs (i.e., the uterus).

The “ovariohysterectomy” procedure, by contrast, refers to the removal of both ovaries and the uterus. As such, this procedure takes out all major reproductive organs, thereby ensuring no reproductive tissue could ever meet any untoward end (cancer, infection, etc.).

In either case, any dog undergoing these procedures is considered sterilized. So whether we take out the ovaries alone, as in the German-spayed dog’s case, or the uterus and the ovaries, as it’s commonly done in the U.S., the procedure is still colloquially known as a “spay” –– despite what she may have gleaned after communicating with her veterinarian.

So why the difference?

Veterinarians learn how to spay pets differently in different countries. US veterinarians tend to take out the ovaries and the uterus while most European vets remove the ovaries alone.

Not surprisingly, the debate among veterinarians on this point has often been heated. European vets can’t for the life of them figure out why their U.S. colleagues take out the whole thing when all that’s required to prevent pregnancy is that we take out two small bits of tissue.

Meanwhile, most vets on my side of the pond argue that getting rid of the uterus can help prevent some serious issues in the future. So why not get it all out while you’re already in there, they ask?

On the surface, this argument seems to makes a lot of sense. After all, uterine infections and uterine cancer are still theoretically possible if the uterus is left behind.

In European studies, however, uterine infections have not been found to cause a problem. That’s because removing the ovaries means no more of the hormones whose fluctuations give rise to uterine infections.

And uterine cancer? At a prevalence of 0.003 percent of female dogs, it’s not a compelling enough reason to remove the uterus, claim European vets.

In fact, when you consider that excessive bleeding, anesthetic risk, and incision infections top the surgical complication list for spay patients, it makes sense that we would remove as little as possible, as fast as possible, with as tiny an incision as possible. And that’s exactly why European veterinarians prefer ovariectomy over the slightly more involved ovariohysterectomy. After all, two things are easier to remove than three.

So why do we still spay the way we do here in the U.S.? Because that’s how we learned to do it and, therefore, it’s how we remain most comfortable doing it. In fact, despite the fact that fewer slices of the scalpel are indicated for an ovariectomy, it’s actually faster for us to perform the procedure our muscles first warmed up to so many years ago.

But is it really best?

To my way of thinking, it most certainly makes more sense to spay the way the Europeans do. But old habits die hard. Which is why, so far, I’ve only ever undertaken this approach in cases where bleeding is of especial concern (large overweight dogs, in particular).

Back to my German correspondent’s misunderstanding:

In this case, I clearly indicated that a “leftover” uterus alone was no good reason for a follow-up “spay,” which I’m sure is not what her veterinarian was recommending, anyway.

Hence, how I finally succeeded in talking her off the ledge she’d been leaning over ever since she’d come to believe her dog needed another major abdominal procedure. Apparently, some things –– like the spay –– are easily lost in translation.