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You’ve heard about the evidence that spaying a dog might predispose her to
certain cancers but have decided to spay your puppy, anyway. Your decision is a reasonable one.
Although some research suggests that spayed dogs may be at higher risk for malignancies that include osteosarcoma (bone cancer), mast cell tumors and lymphoma, the results remain somewhat equivocal. It is known with certainty, on the other hand, that spaying a young puppy virtually eliminates her risk for mammary cancer — one of the most common types of malignancies to strike female dogs. It also eliminates the risk for unwanted pregnancies. One romp off-leash for an unspayed dog or one determined male dog’s actions could leave you with a litter of a half dozen pups. With almost one million unwanted dogs euthanized at shelters each year, it’s a potential burden you just don’t need.
But should the uterus be removed along with the ovaries? After all, taking out the ovaries by themselves will do the trick of making it impossible for a dog to become pregnant.
In Europe, it has been standard procedure for decades to remove only the ovaries. The procedure is called an ovariectomy. But in the United States, veterinarians have traditionally removed the uterus as well (ovariohysterectomy). The thinking has been that leaving the uterus behind can lead to pyometra — a potentially deadly uterine infection.
But there are now convincing data that if pyometra takes hold after a spay, it’s usually because a bit of an ovary was mistakenly left behind, not because a portion of the uterus was left behind. While the uterus is the site of the infection, it only develops because of the estrogen and progesterone production of the ovaries. “Once the ovaries come out completely, the uterus shrinks and atrophies,” says Tufts surgeon John Berg, DVM, the editor-in-chief of Your Dog. “It is very unlikely to become infected.”
In the not-too-distant future, Dr. Berg believes, many veterinarians in the U.S. will go the way of Europe and remove only the ovaries during a spay rather than the ovaries and uterus together. It’s not just because removing the uterus is unnecessary to prevent pregnancy. It’s also that ovariectomy can often be performed with a 2- to 4-inch incision, whereas ovariohysterectomy incisions are usually somewhat longer. In addition, more and more spays are being performed by laparoscopic ovariectomy, with tiny 1/2-inch incisions. Laparoscopic ovariectomy is a relatively easy procedure to master, while laparoscopic ovariohysterectomy is somewhat more difficult.
