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Two Ways of Spaying a Cat: Ovariohysterectomy vs. Ovariectomy

Posted July 30, 2015 in Cat Surgery A-Z

Kitten on a couch

Zee Mahmood, a veterinary technician in Reading, PA, contributed to this article.

Have you ever wondered why your family veterinarian always encourages you to have your female cat spayed? There are many reasons for this recommendation, including prevention of several deadly conditions such as an infection of the uterus (pyometra) and breast cancer (mammary tumors).

During a spay, the reproductive organs (i.e. the ovaries and the uterus) are removed. In the US, the spay surgery is called an ovariohysterectomy. This means that the ovaries (ovario-) and the uterus (-hyster-) are removed (-ectomy). This, however, is not the only way to spay a cat. The ovariectomy is frequently performed in other countries: the uterus is left in the belly, while only the ovaries are removed.

Why do we generally remove the uterus in the United States?
The reasoning is that diseases of the uterus are prevented by removing it. No uterus = no future disease related to the uterus. In many European countries, however, this argument doesn't fly. The ovariectomy has been practiced for decades in Europe, among other locations, with reportedly no increase in the numbers of patients with future diseases of the uterus. In fact, an article I read in a small animal surgery magazine stated that "there is no definitive advantage for removing the uterus in addition to the ovaries." The article goes on to describe how an ovariectomy is (logically) less invasive and faster than an ovariohysterectomy1. This also means anesthesia time is shorter with an ovariectomy.  

Is an ovariectomy less risky?
Complications are rare with both procedures, but similar. Complications in either case may include:

However, there is a greater risk of bleeding when the uterus is also removed. Again, while any complication is rare, I believe in the popular phrase of veterinary medicine, "First, do no harm;" therefore, it is hard to agree that removing the uterus is a better choice than leaving it in place.

But doesn’t it make sense that removing the uterus eliminates the risk of certain diseases?
Interestingly, what happens is that once the ovaries are removed, the uterus atrophies, or shrinks away and basically dies on its own. The end result is therefore the same: no uterus = no risk of pyometra and no tumors of the uterus.

What are the limitations of an ovariectomy?
One important limitation of the ovariectomy is that it should only be performed in young, healthy females with a healthy uterus. Older females should have an ovariohysterectomy performed.

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Dr. Phil Zeltzman is a board-certified veterinary surgeon and author. His traveling practice takes him all over Eastern Pennsylvania and Western New Jersey. You can visit his website at, and follow him at