Why Spay?

I hope everyone has had a chance to be outside this weekend to enjoy the unseasonably warm weather! I’ve still got a gut feeling that we’re going to pay for this later with bad weather but I’m not about to miss a chance to enjoy it.

I still want to cover a topic today that I believe isn’t as well explained as it should be: spay surgery. I always welcome respectful debate about topics I cover, so I hope to encourage readers to ask questions or offer opinions. I have to manually approve each comment that’s made, so it may take a day for them to appear on the blog.

Commonly called a “spay,” this surgery is actually an ovariohysterectomy (OVH or OHE). It’s performed under general anesthesia with the obvious intention of preventing pregnancy in a female dog. Female dogs that are going to be used for breeding can’t be spayed, of course. If an owner is absolutely certain that a dog will be having a litter of puppies, there’s really no discussion to have. In the US, veterinarians remove both ovaries and almost all of the uterus from a female dog. In other parts of the world, the surgery may be only an ovariectomy, with just the two ovaries removed.

Most veterinary hospitals recommend that all female dogs get spayed. The age at which the surgery is performed is variable and ranges from 16 weeks to 6 months. The procedure is extremely routine for veterinarians. That’s a good thing! Procedures we do frequently have better outcomes and fewer complications. Patients are usually recovered by 10 days post-operatively. In most cases, I don’t think clients are given enough information about the procedure, why it’s important, and what to expect during and after the surgery. Clients are left with questions and anxiety. I can talk more about the procedure itself at another time if anyone is interested.

Population control is one of the most commonly cited reasons for spaying. The harsh truth is that far, far too many dogs are put to sleep in the US each year because they do not have homes. Most families are utterly unprepared for the amount of work (and cost) involved with having a litter of puppies, especially if the dog becomes pregnant against the owner’s intentions. Please don’t misunderstand. Population control is good! It’s a social and ethical goal that is sometimes hard for clients to connect with.

There are other direct health benefits from a spay. First of all, we eliminate the risk for cancer in the ovaries. Removal of the ovaries also stops the dogs from having heat cycles (estrus cycles). If the uterus is removed, we drastically reduce the risk of future uterine infections. If a female dog is spayed before her first heat cycle, we reduce her risk of developing mammary (breast) cancer by about 90%. If she is spayed after her first heat, we only reduce the risk by about 70%. That may not sound like much, but if it’s YOUR dog at higher risk, it’s risk that’s directly tied to you and your pet’s well being. I have lots of owners tell me that they “just want to have one litter,” then spay the dog. I also hear frequently, “We think it will be good for the kids to see our dog have a litter.” The vast majority of these clients never do breed the dog, which puts her at risk for the problems just mentioned.

Let me be clear: not spaying your female dog puts her at higher risk for two types of cancer and/or a life-threatening uterine infection. I don’t say this to use fear as a tool or a weapon. I think it’s critical that owners understand what the consequences of their choices are. In the last 5 months at Pet Authority, we’ve had at least 4 uterine infections and three mammary tumors. All of these dogs were unspayed females between 5 and 10 years of age. These are very real consequences that we see in practice.

In order to be fair, I need to mention some of the possible complications of the spay surgery. We do have to open the abdomen during this procedure, so complications with the incision (hernias, the incision opening up, etc.) can occur. These things are very rare if the post-operative rules are followed closely. Spayed dogs do have a lower metabolism than unspayed dogs, so they will not need as much food. (Spaying doesn’t make dogs fat. Overfeeding does.) Some female dogs will develop urinary incontinence at some point after the spay. We believe that this is related to the lack of hormones that the ovaries would normally release. This incontinence is treatable and in almost all cases and will be controlled as long as the dog stays on the incontinence medication.

Each owner needs to weigh the benefits, disadvantages, and costs associated with doing or not doing the spay procedure. Having an adult female dog spayed because she has a uterine infection more than doubles the cost of the surgery. It’s a higher-risk procedure because the dogs are already sick. I’m aware that a spay is not a cheap procedure. I wish we could make the surgery less costly without sacrificing patient safety. I also don’t believe owners would be comfortable hearing from us that we can do something at less cost with “only a little more risk.”

The bottom line, in my opinion, is that we can do a female dog a lot more good by spaying her than by not. We can minimize risk during anesthesia with good, safe practices. We can eliminate or reduce some cancer risks. We can nearly eliminate the chances of a life-threatening infection occurring. I just don’t see where the drawbacks are.

Thanks for taking the time to read my perspective on a somewhat controversial topic. Please ask questions, share information, or offer your opinion. Respectful debate is a healthy, beneficial thing. 🙂



Filed under preventive care, surgery

8 responses to “Why Spay?

  1. Chris

    There are a few surprises in this post, I’m shocked to say. I totally agree that spaying to control overpopulation is critical. I did know about the risk of cancer that it reduces, but I never heard about the risk of uterine infection or the 20% increase in cancer risk after having a litter of puppies. Even more reason to have the surgery done as soon as she’s old enough! Kids can probably see a litter being born on YouTube these days. No need to put a beloved pet through that and add even more dogs to an already overcrowded population.

  2. Val Lewis

    I, for one, would love it if you would talk more about the procedure itself. In this statement: In the US, veterinarians remove both ovaries and almost all of the uterus from a female dog. What is meant by ‘almost’ all of the uterus? Then: In other parts of the world, the surgery may be only an ovariectomy, with just the two ovaries removed. Are there advantages to leaving the uterus? Reasons for not leaving one overy for hormones and possibly avoiding later incontinence?

  3. Reducing that cancer risk is the main reason that I’m more pushy about female dogs than males in terms of a sterilization surgery. While it’s never too late to spay or neuter, the female dogs gain the most benefits if the surgery is done before the first heat cycle.

  4. I’ll see what I can do about a tour of a spay. I should be able to set up a new post with pictures to show you parts of the procedure. I can probably do that for the Thursday post this week.

    “Almost” all of the uterus refers to the fact that while we remove both ovaries, and both horns of the uterus, a small part of the body is left near where the uterus attaches to the vagina. It’s a difficult area to work in a lot of the time because of the proximity of the bladder, colon, and pelvis. This “stump” is sealed by scar tissue and doesn’t pose any trouble. It’s tied off so that the genital tract just comes to a dead end rather than being open into the abdomen. In extremely rare instances, this stump can get infected and cause a “stump pyometra.” The conditions for that to happen tie right into your second question…

    The ovaries produce the hormones that govern the reproductive cycle of the female dog (physical and behavioral). If we were to leave one or both in place and take away the uterus, the dog would still have heat cycles. The stump could undergo the normal changes associated with the uterus preparing to have puppies, which means that there’s a chance for bloody discharge, followed later by the chance for a uterine infection. Leaving an ovary in place would certainly help eliminate the risk of incontinence, but we’d lose all of the other benefits from the spay.

    The reasoning behind leaving the uterus and taking away just the ovaries seems to center around two things: patient safety and physiology. Any time a surgery can be made shorter, it’s safer for a pet. The procedure also avoids having to tie off the uterine arteries, which must be done if the uterus is to be removed. Without the ovaries, the uterus should remain quiet and mostly inert, so there is some support for the idea that it’s not essential to remove it. This is one of those spots where dogmatic thinking causes a particular method to persist even when there’s good evidence that it’s not adding positively to the longterm outcome for the patients.

    To date, I’ve not had a client request ovariectomy instead of ovariohysterectomy, but I would certainly be willing to perform the procedure that way if requested.

  5. Lisa

    Good article, Dr. Hutchinson!! The vast amount of dogs put to sleep, not to mention the ones who are sitting in shelters and rescues are reason enough for me to firmly believe in spaying/neutering. I wish there were homes for them all!

  6. Thank you! Here’s a chilling fact from the ASPCA that underscores your point:

    Approximately 5 million to 7 million companion animals enter animal shelters nationwide every year, and approximately 3 million to 4 million are euthanized (60 percent of dogs and 70 percent of cats). Shelter intakes are about evenly divided between those animals relinquished by owners and those picked up by animal control. These are national estimates; the percentage of euthanasia may vary from state to state.

  7. David

    In the last 5 months at Pet Authority, we’ve had at least 4 uterine infections and three mammary tumors.

    For context, how large is the (canine) patient population of your practice?

    I imagine there must have been controlled studies that measure the health risk/benefit tradeoff of spaying and neutering, but on this particular topic it’s hard to find objective information.

  8. I can’t give many specific numbers, but I can tell you that I see about 300-400 patients per month, 75-80% of which are dogs. The vast majority of those dogs are spayed or neutered already. I don’t have a handle on what % of them are intact, but my gut feeling is that most of those patients end up having some sort of problem related to their reproductive status.

    There have been many studies looking at the benefits and risks of sterilization surgery, as well as many more examining the prevailing attitudes of veterinarians in various countries with respect to time of spay/neuter, etc. It’s still difficult to sort through it all. There are so many factors that influence the numbers, including the question of how many intact dogs never present to a veterinarian at all.

    I try to be practical about the situation. If I inform owners about the benefits and risks, possible complications, best care for the patient, and costs, they’re usually able to make a decision they will feel comfortable with longterm.

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