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Spaying Your Pet Too Young

Vulvar Invagination, aka: Involution, Recessed Vulva, Hooded Vulva, "Innie" Vulva



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Ron Hines


Ron Hines DVM PhD

Back to When To Spay - When To Neuter Article

Click On Any Image To Enlarge It

I mention in several of my articles that the sex hormones, estrogens and testosterone, have many functions in your pet’s body other than fertility. One of those important functions at puberty is to mold  the shape of the pet’s final portion of its urinary/reproductive tract (the labia, vulva, clitoris and vagina). During that molding process, it is changed from its infantile, poorly-developed form into its normal mature shape. When those hormones of sexual maturity are removed too soon, some dogs and cats are left with an abnormally small, indented organ.

Not all cases of vulvar invagination are related to the age at which your pet was spayed. Some cases have a genetic basis and are seen in un-neutered as well as neutered females. Cases are also more common in the “wrinkly skinned” breeds and those with flabby skin tone.  But I see it most often in pets that were spayed before their first heat cycle. The earlier in the puppy’s life that the surgery was performed, the starker it generally appears. It also appears to me that later in life, incontinence is more frequent in those early-spayed dogs as well but I know of no one who published studies on either problem. It is just my personal observation over many years.

Not all the estrogens that matures your pet’s genitourinary tract originate from its now-missing ovaries. Some is produced in its adrenal glands which are still present and elsewhere and, perhaps that spares some of the dogs these side effects. 

Look at the two photographs in the top row above. Both show the vulvar problem this article pertains to. The photo on the left in the second row is what a normally-conformed adult female dog should look like - whether it was spayed or not. In the case of an unsprayed female, it will be larger if it is approaching or experiencing a heat cycle. The last photograph is the result of complex surgery to restore proper conformation (vulvoplasty, episioplasty).  My photo of the surgery to correct this problem does not indicate it’s seriousness and complexity – for that go to Google images.  

When an adult pet is left with an invaginated, immature genitourinary tract orifice, urine does not drain properly during urination. The area remains damp, urine scald occurs and the dog licks the area traumatizing it. Dark acne-like spots often begin to surround it. Elements in the pet’s saliva stain the surrounding hair brown.

The surface of your dog’s skin has a natural population of bacteria – all animals and humans do. They are kept in check by the outer defensive layers of our skin.

When that skin surrounding the vagina is traumatized, due to persistent dampness, urine scald and licking, bacteria that can be quite unhealthy tend to predominate (staphylococcus="staph", pseudomonas, corynebacteria) (ref) and the pet develops symptoms.

So about that time, many owners take the dog to a veterinarian and are told that it has a UTI. That is technically correct; but it did not occur out of the blue. It occurred because of the unhealthy shape of its final genitourinary system. Those pet owners generally leave with an antibiotic and are told to give it  for a week or two. If the urine stream is cultured, it yields bacteria.  But often, those bacteria have not moved higher up the urinary tract - yet.

This is not the common vaginitis of puppies that resolves itself with time. It is not the UTIs common with dogs that have bladder or kidney stones or those that develop urinary tract infections due to diabetes or geriatric incontinence. But it is one of the most common causes of UTIs in dogs.

Oral and injectable antibiotics do give the pets temporary relief. But nothing short of surgery and, perhaps, hormone therapy (ref) , might permanently cure it. The use of estrogen hormone therapy in sizable amounts in dogs is not without serious risk. (ref)


When your pet receives multiple courses of antibiotics for chronic infections, the chances are high that bacteria will eventually develop resistance to those antibiotics. Such is the case with the staph that are commonly involved. (ref1, ref2) Those resistant bacteria are not only a threat to your dog; they are a threat to you and the human members of your family as well. Whatever bacteria your dog harbors are probably already living in and on you as well and vice versa.  (ref1, ref2) There is nothing wrong with that when they are healthy, non-pathogenic bacteria that are not antibiotic-resistant.

So besides doing next to nothing for solving the pet over-population problem, these early age spays and castrations can lead to a variety of lifelong medical issues for your pet and for you. (ref1, ref2, ref3)

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