Is It Too Late to Spay My Dog (when is too old)?

It’s never too late to spay a dog…or is it? If your female dog is old and entire then it’s important you understand the benefits of getting them spayed, the risks of leaving them intact, as well as the risks of spaying itself.

is a dog ever too old to spay?

My female Chihuahua is 8½ years old and not spayed. She’s never tried to run away and she’s a house dog but for health reasons I’m considering getting her spayed and I’m just wondering if it is worth it now?

So question number two is from CourtMikay who’s considering getting her female dog spayed, and wondering if it's actually too late to spay her female dog.

Benefits of spaying

So really, if we're thinking of spaying, there are three big reasons and benefits for spaying a dog.

  1. Prevent pregnancy

  2. Prevent pyometra

  3. Reduce breast cancer risk

The first of those is to prevent pregnancy, the second is to prevent a condition called pyometra, which is an infection of the uterus where the uterus effectively becomes a big balloon full of pus that's really horrible and potentially life threatening and I'll get onto that in just a minute. And we also want to reduce the risk of mammary tumours. So those are the big benefit of spaying a female dog in general.

Is it too late to spay an old dog?

Pregnancy risk

Now at 8 ½ years old, a dog is less likely to get pregnant. Certainly older dogs can still get pregnant but she also a house dog, so she's probably unlikely coming into contact with entire male dogs. This factor is less of a risk and less of a consideration with this particular Chihuahua.

Mammary cancer

There's also less benefit for a reduction in mammary tumors in older female dogs. We tend to believe that if we're spaying a female dog before their first season we get about a 99.5% reduction in the risk of mammary tumors. If we're spaying before the second season, it's about a 95% reduction, and before the third season about a 75% reduction.

Now spaying later than this means there doesn't seem to be such a big difference in the risk of a dog developing breast cancer. Having said that though, there does seem to be an increased survival if a dog has been spayed within two years of mammary masses developing. That is being spayed up to 2 years before the mammary tumors developed

Mammary cancer is really pretty common in entire old dogs, and about 50% of those that do occur are nasty, malignant tumors. This means they can spread to other parts of the body and they can ultimately be fatal. Benign tumors are not always harmless, and can grow very big, causing severe problems as well.

Given that the two-year survival from mammary cancer is better if a dog has been spayed within the last two years means that there’s still going to be a potential benefit I think in spaying this particular dog from a breast cancer survival aspect.


Now moving onto pyometra, or an infection of the uterus, one in four female dogs will develop pyometra by the time they get to ten years of age if they remain entire. While this condition does have about a 95% survival rate if it's treated appropriately, it does require expensive emergency surgery in the majority of cases.

Now some cases of pyometra can be managed medically, but these are really the minority of cases where this is preferable. Emergency surgery generally gives us the best outcome and is the preferred treatment and either way, both are still kind of severe interventions and they're expensive treatments that carry some risk as well.

So those are really the benefits of spaying and I think they highlights the fact that in an older dog, there still is going to be a benefit to getting them spayed at this age and even later. Pyometra is that common and it's much better to have an elective surgery when a pet is otherwise healthy than to wait until they're really sick. There's also going to be a big cost difference there as well, which is maybe something to consider depending on your financial circumstances.

There are 3 big reasons and benefits for spaying a dog: prevent pregnancy, prevent pyometra, and reduce breast cancer risk

Risks of spaying an older dog

Anesthetic and surgery risk

Now having said all of that, there's no such thing as a no risk procedure or no risk surgery procedure. So the main risks of spaying any dog are that an anaesthetic and a surgical procedure does carry some risk. This risk is going to depend, to a certain extent, on the health of the individual.

We can do pre-anaesthetic blood testing to check that the liver or kidneys and the rest of the body function seems to be working well. We can give IV fluids, intravenous fluids, during the operation and I think that's not an option, it’s really a necessity for an older dog like this.

Really though, unless there's specific individual concerns because of other diseases being present, or blood test results showing that there may be something else going on, the risk of surgery really is very low. This is the case in a young dog as well as an older dog (and at 8 years old, this Chihuahua may only be half way through her life!).

Spayed dog side effects

Now there are also potentially some side effects to being spayed. There are some potential risks in certain breeds if spayed before twelve months of age. So that's cruciate disease, bone cancer and numerous other ones. There doesn't seem to be any risks or there's no known, proven risks in spaying a female dog older than that and certainly in an older dog like this Chihuahua.

I don't think we need to be worrying about these things in an old dog, and I've actually got a separate article that really is a comprehensive review about the risks and benefits of spaying a female dog in general.

The bottom line

But I guess the summary is that yes, I think it's definitely still worthwhile to get an older dog spayed. We're going to potentially avoid some really emergency conditions and I think a lot of the potential side effects of being spayed are not going to be a risk in an older dog compared to getting a younger dog spayed.

The above is a transcript taken from “The Dr Alex Answers Show”.

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