Top 10 Reasons To Spay Your Pet

Dr. Phil Zeltzman is a mobile, board-certified surgeon in Allentown, PA. Find him online at He is the co-author of “Walk a Hound, Lose a Pound” (

Chris Longenecker, a Certified Veterinary Technician in Reading, PA, contributed to this article.

Should you have your female cat or dog spayed? Are you on the fence? Are you dreaming of puppies and kittens? Deciding to spay a pet is sometimes a controversial, sensitive, even emotional topic. In addition, there are many myths out there...

There are many medical reasons to spay pets. Let’s go over just 10 of them.

1. Breast tumors
Over 25% of non-spayed female dogs will develop breast or mammary tumors! Spaying pets protects against them, depending on the timing. The risk of a dog having mammary tumors is 0.05% if a female is spayed before the first heat.  Then it shoots up to an 8% risk after their first cycle, and 26% after their second heat. If a dog is spayed after 2 years of age, then there is no more protection. However, it will protect her against other conditions, including pyometra (see below).  This is the reason why most vets typically recommend spaying before the 1st heat cycle.

In dogs, approximately 50% of mammary tumors are benign and 50% are cancerous. In cats, 90% of mammary tumors are cancerous, so spaying is even more important.

2. Pyometra
Pyometra is a serious condition where the uterus fills with pus. It is common in non-spayed dogs, and unusual in cats. In turn, pyometra can affect many organs, which can make a pet very sick or even kill her. One of the organs that classically gets damaged is the kidney. It can get worse: a “mature” pyometra can rupture or break. This leads to having pus all over the belly (septic peritonitis). Such patients can still be helped with more intensive care.

3. Unplanned pregnancies
Letting a non-spayed cat or dog roam is similar to gambling. Chances are, our little female friend will meet Mr. Not-Right.

Now… not only do you have to deal with the pregnancy, but in 2 months, you will need to make sure that the delivery goes well. Then you will have to keep the 1, 2, 3… or 10 babies or find them anew home. If mom can’t nurse, guess who needs to get up every 2 hours to bottle-feed the babies?

Multiply that by one or ten or one hundred thousand, and you start to understand the complex problem of pet overpopulation. This leads to millions of abandoned or euthanized pets. 

4. C-sections
Sometimes, natural delivery just isn’t possible for health or anatomical reasons. Bulldogs, Chihuahuas and Yorkies are some of the breeds with an increased risk of needing a C-section. 
A C-section is a wonderful event at a vet clinic when everything goes well. We love helping puppies and kittens come to life. But for the pet owner, it can be a stressful and expensive ordeal. 

5. Heat cycles
As a general rule, most females have their first heat cycle around 6 months of age, which is why we often recommend spaying before that age. A heat cycle causes mood swings (doggie PMS?), swollen nipples, attraction of males, a swollen vulva and a bloody discharge. It can be quite stressful for everybody involved.

6. Ovarian diseases
Sure, diseases of the ovary, such as tumors, are rare. But a real good way of eliminating that risk is to spay a patient.

7. Tumors of the uterus
Likewise, tumors of the uterus are not common, but spaying eliminates this risk. Most vets however remove ovaries and uterus (ovario-hysterectomy). Some vets do not remove the uterus and only remove the ovaries in young, healthy pets (ovariectomy).

Fear not, research and decades of experience prove that removing the ovaries only (again, in young, healthy pets) does not lead to an increased risk of diseases of the uterus. In fact, the uterus virtually disappears after an ovariectomy. 

8. False pregnancy
False pregnancy is a strange and stressful condition where a pet is convinced that she’s pregnant… when she’s not! Females show nesting behavior (i.e. they literally make a nest for her imaginary offspring), their belly gets bigger, and they produce milk. Spaying can eliminate the possibility of this condition.

9. Eclampsia
Eclampsia is a life-threatening complication of pregnancies.  A pregnant female can have calcium levels that are dangerously low (hypocalcamia). This condition can lead to shaking or seizures, even heart complications. This is a major emergency that requires IV calcium and fluids.

10. Genetics
There are countless genetic diseases, such as hip dysplasia, heart disease and eye conditions. Spaying a female who carries the bad genes is the easiest way to prevent babies with the same problems.  Only through reasoned breeding can a breed improve over time. 

Again, these are only 10 of the reasons to spay a pet. Spaying also prevents behavioral problems and several other issues. Clients who don’t have their pet spayed often tell us that they couldn’t afford the procedure at the time.  Please keep in mind that it could cost 5 or 10 times as much to treat mammary tumors or pyometra.  Worse: pyometras often seems to happen after hours (read: at the local emergency clinic on a Sunday), which increases the cost even more.

So please talk to your family vet about your particular pet to make an informed decision.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.

Reviewed on: 
Monday, April 6, 2015