Adrienne is a certified dog trainer, behavior consultant, former veterinarian assistant and author of Brain Training for Dogs.
What Does It Mean If a Dog Has Been Spayed?
A dog who has been spayed, or fixed, has gone through a surgical procedure that is technically known as ovariohysterectomy, also more commonly known as spay surgery. This means that the female dog's reproductive tract has been completely removed, including her ovaries, oviducts, uterine horns, and uterus.
Without these reproductive organs, the dog cannot get pregnant and can no longer get twice-a-year heat cycles (or once a year, depending on breed) that are triggered by hormones.
If you don't know if your dog has been spayed or not, don't worry—you're not alone! Countless new dog owners go through this exact same dilemma. The shelter may claim that the previous owners had the dog spayed. However, can you trust this statement alone? What if the owners didn't know for sure? What if they were trying to hide the fact that their dog wasn't spayed? This is important information to know, especially if your neighborhood is full of intact males.
Signs a Dogs Has Been Spayed or Fixed
Unfortunately, there are no outwardly visible signs that indicate if a dog has been spayed or not; however, there are some clues that can help you figure this out, including:
- A spay incision
- Smaller secondary sexual traits
- Absence of heat cycle
- Medical records
- Information provided by a tattoo or microchip
- Hormonal tests
- Exploratory Surgery
Your vet, of course, would be more experienced in detecting these signs and determining which tests may be most appropriate. Let's take a closer look into several of these signs and "diagnostic tests."
Signs That a Dog Has Been Spayed
Unfortunately, your dog won't tell you if she is spayed or not. Even if she could talk, she wouldn't even be able to remember the procedure, as nowadays dogs are spayed often when they are very young (especially if you got your dog from a shelter) and they are put under anesthesia. However, there are some clues to help you figure it out.
Look for a Spay Incision
Spay surgery requires the dog's abdomen to be opened in order to remove the reproductive parts. In most cases, the dog will have had stitches that might have been taken out or absorbed. Because of this procedure, most spayed dogs will have an incision.
This incision, however, may not be easy to detect. It is quite small and difficult to see. You may need to shave your dog's belly to see the scar. The scar is located in the dog's ventral midline.
If you do happen to see or feel an incision on your dog's abdomen, consider that a prior hernia or a cesarean surgery may have left a similar scar. It's best to see your vet for confirmation rather than end up with a litter of unexpected puppies!
Check for Secondary Sexual Traits
You may notice how a spayed dog's mammary glands, nipples, and vulva are smaller compared to those of intact, non-fixed females. However, according to the ASPCA, there is no concrete evidence that grants any significance to this size difference.
Wait for a Heat
In some cases, you may just want to wait until your dog displays signs of a heat. Of course, during this time, treat her responsibly, as if she was intact.
Dogs generally go into heat every six to seven months, but there are many exceptions, depending on the breed. For instance, if you own a female Basenji, you may be forced to wait a whole year if she recently went into heat before you got her, as these dogs tend to go into heat just once a year (generally in the fall).
Of course, even in this case, there are exceptions. Sometimes, a dog who has been spayed will still go into heat if some ovarian tissue was left behind during the surgery. In this case, the dog may still produce hormones that cause the symptoms of a heat cycle to kick in, even if the dog has been spayed. This is quite rare, but it's worth a mention!
Investigate the Dog's Medical Records
This may be a bit tough, but you may be rewarded if you can find your dog's medical records. For instance, if you know the name of the previous dog owner, you can call several vet offices in your town and see if they still have the dog's medical records.
While client confidentiality must be maintained, sometimes people are willing to tell you if a dog has been spayed or neutered once you tell them about your dilemma. If your town requires dogs to be licensed, you may also get some help by calling animal control or the local city hall, as they often record this type of information.
Check for a Tattoo or Microchip
In some cases, dogs are tattooed for identification purposes. Along with their identity, their reproductive status is also recorded. And don't forget to check for a microchip—this little chip can contain important information, including if your dog has been spayed or not. You'll need a universal reader, which can be found at your local vet or shelter, though the shelter should have checked for microchips before giving the dogs up for adoption.
As you can see, there are several ways to determine if a dog has been spayed or not. A combination of these factors is a good indicator that your dog cannot give birth. Always consult with a veterinarian to determine your dog's reproductive status and never make assumptions—they can end up being costly.
Ask Your Vet for Hormonal Testing
Your vet may provide some options should a spay incision be difficult to detect. In some cases, the vet may check for a specific hormone, or they may take a look at cells collected from the vaginal wall.
For example, you can tell if a dog is fixed by measuring the amount of luteinizing hormone present in the dog's blood. A great percentage of spayed dogs have high levels of this hormone in their blood, whereas intact animals have lower levels.
However, keep in mind that about 22% of tested intact dogs also have high levels of this hormone. This is because intact dogs undergo brief episodic surges in the luteinizing hormone concentrations.
Alternatively, the vet may inject a hormone and then take a few blood samples afterward to check for ovarian activity. While these tests are not fool-proof, together they can help provide a clearer picture that, according to the Oklahoma State University Boren Veterinary Medical Teaching Hospital, can save a dog from undergoing an exploratory surgery.
In general these tests can be used to gain some insights about a dog's hormonal status: vaginal cytology sample (to check for cornified epithelial cells indicative of estrogen stimulation) luteinizing hormone test, serum progesterone concentration and anti-Müllerian hormone assay (measures Anti-Müllerian hormone, AMH).
Ask for an Ultrasound
Although an ultrasound can provide insights on whether a dog was spayed or not, it can be challenging checking for those cases of dogs who have been spayed but have some ovarian tissue left behind. Ovarian remnants may be located virtually anywhere in a dog's abdomen and can be challenging to find even by the most experienced ultrasound users.
Finally, as a last resort, the vet may decide to go into surgery and do an exploratory surgery. Most often, this is the case of a dog who is spayed and has some ovarian tissue left behind which is difficult to detect and may need a more "hands on" approach to detect and remove.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2013 Adrienne Farricelli
Adrienne Farricelli (author) on November 08, 2019:
Your vet should be able to tell whether she is spayed or not by looking for a scar and additional testing. I am not aware of the exact costs for checking her hormone levels, you can try to call around your local vets as prices may vary considerably based on location. An ultrasound can come handy as well to check for reproductive organs.
Laswanson57 on November 07, 2019:
Three years ago I adopted a female dog. Her nipples and vagina were very pronounced. I was told to wait for her to go into heat because we weren't sure that she was spayed (I took her to the pet store for vaccinations). A few months later, she went into heat and I took her in to be spayed. Her vagina and nipples receded after the surgery, and she has a tattoo. Now I've adopted a foundling. Again, extremely pronounced nipples and vagina. There is no sign of a tattoo and considering how traumatized she was when I got her, it's a pretty sure bet that her former owner, whoever that may be, didn't get her spayed. What if she doesn't go into heat? With my other dog, I was told to just wait to spare her the pain and trauma of surgery in case she had been spayed. Is the hormone test to determine ovarian activity expensive? I've always spayed/neutered my dogs for their health.
Andy on May 03, 2019:
anti-Müllerian hormone (AMH) test.
Adrienne Farricelli (author) on May 05, 2013:
Thanks for stopping by Midget38! I went through this puzzle as well a few years ago with a dog I fostered.
Michelle Liew from Singapore on May 04, 2013:
Great tips especially for those who are thinking of adopting, but not sure how to go about it. Thanks for sharing!
Adrienne Farricelli (author) on May 04, 2013:
Thanks for the votes up Eiddwen. I dealt with this situation with a foster dog and wasn't sure if she was spayed or not as the rescue had no clue.
Eiddwen from Wales on May 04, 2013:
So very interesting and also so useful to all dog owners. Voting up.